Ferminal said:The comparison to Hinault LeMond Fignon Merckx etc is to show that GT winners gave a clear indication of their potential from a very young age, always <25 and within their first few GTs. If blood doping was never invented there is reason to expect today's greats to follow a similar path of success. That is not to ignore the other dynamics in the sport which probably mean it would happen a bit later anyway.
For me though the foremost explanation is that young riders don't often get on an elite program in their first few seasons. They (or their bosses) may be reluctant to dope until they've had a few years relatively clean. Of this decade's top GT riders, those who made the breakthrough early on were those who we know doped at that time:
Contador 2007 - 24, 2nd GT
Andy Schleck 2007 - 21, first GT
Valverde 2003 - 23, 2nd GT
Cunego 2004 - 22, 2nd GT
Porte was doing triatholons at 21, Froome didn't enter pro cycling until 22, now if they had been on pro tour teams U20 then I could see the point but this is not the case.