My comment was about ‘outdoor only’ training.
I agree whole heartedly about most of us loving outdoor rides.
I really love riding my bike for multiple hours on end without feeling like it’s a chore. TR indoor intervals helped me grind up those 30%+ sections of trail when I hadn’t been able to train outdoors very often.
I have my data that proves it. It sounds like you have yours as well.
It’s totally normal for TR to push the trainer efficiency thing. It’s their business, but it also works as described.
You do the plan and your fitness goes up. Win.
10 hrs/week gets you results that equal your previous 15 hrs/week of outdoor riding.
That could be the opposite. Maybe how easily that could be the opposite is the real question here.
This whole efficiency ratio thing doesn’t work IMO. It can never be quantified because it will always be individual to each person and ride.
SFA chance of doing well on the bike if you never noodle around outside.