Not to say I agree or disagree with the reasoning that led us to this point but…
The general hierarchy of cheating appears to be something like mechanical doping is worse than medical doping is worse than gear optimization is worse than training optimization.
There is a fairly clear line for bike racing around what constitutes a race legal bike (both weight and frame geometry rules are clearly defined). Within those confines you can do pretty much whatever you want, but if you break them you are cheating and disqualified. People argue about those rules and whether they should be changed, but (nearly) everyone agrees on those limits. If you were to show up with a motor on your bike, or a recumbent bike you wouldn’t be allowed to race because these things give you an unfair advantage.
Similarly there are fairly well known and understood drugs that will give your body a boost such that you can out perform others who have invested similar time and money into their training.
Now…below the line that we consider cheating are things like getting a good night’s sleep because you can afford a full time nanny to watch your kids or having a personal nutritionist who follows you around and makes sure you’re eating perfect foods all day every day. Also below the line is hiring a professional coach who will monitor your workouts and provide you with real time feedback on your performance such that you can hit your intervals.
For amateurs there is certainly a wide array of things you can do to fully optimize your training, your bike, your aerodynamics, all of these things vary in cost and in benefit but are not generally considered cheating.
I find it interesting how stark the line is in my mind and how gray it is in yours. I regularly compete against people with both significantly more and significantly less disposable income than I have and it doesn’t bother me one bit. I sometimes feel envious of those with less time constraints or those with the money to have spent time in an air tunnel to optimize their position but I also feel grateful that I can afford the time and dedication that I put into this hobby.
For me there is no question that medically enhancing your abilities is outside the rules of the game, the same as putting an aero shield around my TT bike would give me an unfair advantage and be illegal. This is because there are clearly defined rules for these things that I would be violating whereas there are not rules about how I spend my time and money on training, recovery, or my position on a race legal bike.