There is much man wasn't designed for. Walking upright for example. But with training and preparation much can be achieved.
With regards to the cycling, Froome was found to have a high level of salbutamol. I'm betting plenty of others had high levels too along with who knows what else. So if we were to take the little leap that most of the front runners were doping, Froome still beat them all. Maybe if they were all clean the result would have been the same but without lawyers. We'll never know.
Surely though, whoever is prescribing the meds is as culpable as the athlete for taking them? How does one get a 2 year supply of (insert name of drug here), finish it in three weeks and then get another script filled? It's hard enough to buy a box of 24 Nurofen Plus without the pharmacist treating us (well me today) like some sort of opiate addict. Isn't there supposed to be checks and balances in the drug prescribing system?
I'm sure there is a suitable painkiller for that. Just don't take too much of it. But if you do, remember this... I used to work for Sky