that Cat3 and amateurs are now using the means they have been in the pro peloton a long time.
This proves nothing and works both ways.
I know plenty of decent level amatuer sportsmen who use massive amounts of PEDs...they use because they're not pro and not getting tested...they understand fully that they'd have to rethink their PED use if a pro team came knocking on their door...see JTL for an example in cycling, doped up to the eyeballs to secure that big pro contract, once with Sky and subject to pro level testing he was found to be average at best....and got popped to boot.
Just because amatuers are using something doesnt mean the pros are, like i said you can get away with virtually anything at amatuer level due to the lack of scrutiny...amatuers using clunky obvious motors is no indication that pros are using them.
I'm willing to be proved wrong but as Sam wrote, there are too many instances where having a motor in the bike would be easy to discover via crashes, abandoned bikes, cameras on the riders for virtually the whole stage, journos around the pits with cameras, disgruntled team mates, bitter rivals etc...
...the only motors we see are Varjas demonstrating tech that wouldnt fit in the hubs the pros use and incomplete fantasy wheel rim 'motors'...and some TV station shots of supposed downtube motors giving off heat but the images are so crap they're not picking up heat from nearby car's engines yet we're supposed to believe they can detect a bicycle motor!?
Start dismantling and using xrays, its the only way and i fully support it but trying to make out Froome is the chosen one who got a motor in 2011 is laughable...why him?...its very suspicious, donkey to racehorse as the clinic likes to say, much better for someone like Contador to have started motor doping as he was already good and wouldnt attract attention (actually with all his bike changes mid race over the last few years he's a prime suspect for motor doping)...or choose someone else in Team Sky at the time who was thought of as having GT potential so as not to arouse suspicion.
So much about motors doesnt stand up to scrutiny...but we do know doping controls are poor and easy enough to circumvent, particularly if supplemented with 'legal' meds like Tramadol, Telmisartan and clever use of the TUE process...theres your reason for Froome's transformation, he got serious and started 'preparing' properly...its not as exciting as debating motors in bikes but until proven otherwise its good old fashioned doping to me.