Why don’t pro teams go to Sierra Nevada or terenife and setup trainers in the hotel or bus? Seems to me like all the top riders are training on the road.
Why is that? Aren’t there marginal gains to be had that can tip the scales in races that are decided within tenths of 1 percentage point?
So why is an indoor workout better than outdoor I’d you have a powemeter for both
Pro riders typically need to spend many hours in the saddle in order reach their training goals. A 6h training ride is not uncommon and it is a REAL stretch to be able to ride a trainer for 6h straight.
However, I believe more riders/teams are now doing double days, where they may start the day with a 1-2h session inddors on a trainer, then head out a few hours later for a 3-4 hour ride. This accomplishes the goals of increased training effectiveness through riding a trainer, but also allows them to log a lot of TSS by tacking on an additional session.
Your question assumes what pro’s do translates to amateur athletes, but in all likelihood
it does not. go train outside, but for me a trainer is easier and more effective in the time I have.
Indoor workouts are great for building fitness, outdoor workouts are great for building real world and race skills (echelons, pace lines, bike handling, riding in wet/wind, lead out train practice, descending & ascending, reading the race, cornering, braking, etc.).
Besides, a pro’s job is riding a bike, they have all day to waste and can afford to ride their bike outside.
For those of you who work from/at home, do you commute by Zwift every day? 
Not to mention pro cycling is a team sport and they have to learn team tactics, learn each other’s tells and signs and capabilities, as well as practice in real scenarios.
Because these places have the kind of long steady climbs that allow pros to do very structured training on their doorstep using a variety of interval lengths and intensities.
Because pros’ FTP is so high that they can do a recovery interval while still climbing.
Because the pros are training for races that last 4-6 hours, sometimes for 3 weeks on end, and that requires the kind of training volume that would be mentally difficult to achieve on an indoor trainer.
Because in Tenerife, it’s nice and warm all year round.
Because riding and training together as a group helps build up a good atmosphere within the team.
Because you’d need some serious fans and air conditioning to keep a pro cool indoors in a Tenerife hotel.
Etc etc…
Train the way you race!
Races tends to take place on the road and therefore you should train as much as possible on the road. Indoor riding is essentially a different sport. The only reason that I train indoors is because the winters are too cold where I live and a busy work and family life sometimes gives me no choice. Pro cyclists have the luxury to focus all their life aroud cycling so beeing on the road as much as possible is a given choice for them.
As simple as that if you ask me.
guilty as charged… 
- although not consistently and my commute is only 15 minutes 
They are outside so they can flash their sponsors logos.
Only sponsor I have is my wife 
Yes.
I agree in principle with training the way you race, but if I tried to spend hours on my aerobars outside here in Japan, it’s extremely unlikely I’d live long enough to see the race!
And If I lived within a stone’s throw of a nice quiet climb with little traffic and a safe descent, I’d be up there very often. Such is life, I don’t. Not to mention that a lot of my training happens before the family wake up or after they’re in bed, which means it’s dark outside.
The enjoyment of indoor rides and outdoor rides isn’t mutually exclusive.
I know for a fact that being able to train indoor has helped me develop into a stronger rider than would have been possible with only outdoor training.
indoor workouts are not better. While people will argue that it is more controlled, most people are training for outdoor riding and events, and being able to use the bike properly is key: learning to shift properly in order to keep power up is a learning curve, and people rather just hammer on a trainer. Pro’s only warm up on a trainer because of that control before a time trial or criterium (US pros), but maybe just warm up on the road these days.
Indoor workouts are great but only compared to riding in a neighborhood with stoplights and traffic, riding in the rain or snow, riding in the dark, etc.
If you are a pro, you can generally pick where and when you are going to ride outside (and, you’re a pro so you have to ignore rain and cold). Pros, and high end amateurs do most of their training outdoors. They do most of their interval work outdoors.
Trainers do have their place and they are particularly great for time and location challenged folks (like most of us) who can’t ride every day in Tenerife or Girona between 10am and 4pm but general advice on the true nature of Indoor vs outdoor training needs to be taken with a grain of salt when it comes from a company that sells indoor training 
There are many skills drills that can’t be done efficiently or at all outdoors. For example, I was talking to Kate Courtney a few months back about her 2019 season (#1 MTB in the world). A significant focus for her is on cadence. Her coach has her do cadence drills, as tough as 10mins @ 160rpm, on the trainer.
These “either/or” threads are a bit silly, IMHO. This isn’t about “better/worse”, this is about looking at the tools we have available, recognizing the pros/cons that exist in all of them (inside and outside), and choosing to best suit your needs for any given purpose.
Inside training has many advantages, but also some disadvantages. The same can be said for outside training. If a person plans to do competitive riding outside, some amount of blending the two options is most likely appropriate. An all or nothing approach is overly bold and fails to capitalize on the good than can be had from both.
It’s funny to me that we see these discussions and people miss the parallel between inside riding and strength training in a gym. We don’t do squats, dips, bench and other exercises because those motions are “exactly” what we need to do. They are about stressing the body in particular ways to drive adaptations that result in a stronger body.
Insider trainer use is the same in most cases. It is about stressing our muscles and cardiovascular system to drive adaptation. Maybe people are expecting to get more from the inside training since it is a closer connection in body position on a bike and general use when compared to strength training in a gym (that is more abstract to what people are likely doing outside). I think that is OK to a point because we can gain some benefits from the closer specificity of the position and general similarity of training inside to riding outside.
But I don’t see most rational people claiming that inside training serves as a full replacement for riding outside. The pure act of riding a bike, even on the road, requires skill and that should be done outside (shocker). Add in things like group dynamics of riding and racing, or technical requirements of riding off-road, and we see all sorts of reason that we should be riding outside too.
Again, it should not be seen as an either/or. Look at the range of options and pick for your needs. Looking at what pros do with their 20+ hours of time vs the 8 or less hours that most of us have for training (and the fact that we are living “normal” lives with all that comes with them) and I see it as a fool’s errand to justify one or the other with the pro life.
They are doing what they can and need to do with the tools and time they have available. Sure, we can learn some from what they do, but we need to take a wider look at the similarities and differences in their training/lives and those of our own.
I know plenty of flat roads in Memphis where she could do that
Except she probably has a whole list of TODOs for the day. So not having to drive out to your awesome flat road in Memphis probably has an overall positive benefit on her training schedule. I am surprised that someone of your caliber doesn’t know that! 
the other things weren’t listed in the previous discussion between myself and bobmac.
good luck with your training.
My apologies for butting in!
Thanks for the encouragement.
What @mcneese.chad wrote. Many top riders and aspiring amateurs I know supplement outside riding with a couple indoor interval sessions each week. Not all 52 weeks of the year mind you. More when building /getting specific…I’m doing the same more just as a time saving tool to help manage the career/fam…One is not a replacement for the other.