Problem with that is Sky's supposed ZTP and how important it is to them to be seen as clean. If Froome starts performing less dominantly but still well and starts dropping hints he wasn't playing ball, no way do Sky let him do his thing the way Lampre have let Cunego do his. They have to suspend him internally or investigate at least; Lampre do not have such a commitment to the veneer of clean cycling, so they were not beholden to do anything.
Also, of course, Froome's trying to show he's clean and has always been. Cunego was trying to show he was clean by comparing to where he wasn't.
The other question is, where is the talent level of each rider clean? Cunego was a hugely successful junior who was seen as a sure thing when he turned pro, albeit perhaps not as immediate a success as he was. Froome's unusual route into cycling makes it harder to judge where his actual talent level lay prior to rocking up at Barloworld. But because he only showed potential on the odd occasion at Barloworld and after his mildly impressive showcase at the 2008 Tour (where he didn't look as impressive as John-Lee Augustyn, who was younger and even less experienced, and his performances have been ret-conned into showing real star potential as if they were Fuglsang's 2009 Dauphiné or Gesink's 2008 Vuelta) his results then start slowing up.
It's no wonder that for those operating under the assumption he is doping he appears more like Bjarne Riis than Jan Ullrich, and if somebody has been very successful from a young age (or immediately from turning pro, as Bauke Mollema, who took up cycling late and won L'Avenir only a couple of years later, is a good counterexample) it is a lot easier for those operating under the assumption they are clean to explain.