Whilst I'm not inclined to necessarily believe the words or face or body language, Froome has a comically high cadence and that gives me reason to think 'maybe'. Now before you all leap down my throat about cadence and the purported value of high cadence (not to mention it's previous adherents), Froome's cadence - and maybe gearing too, I think he was riding 38/29? or was it 39/28?? - does set him apart from other riders. So maybe MAYBE Sky have been mastering something there (plus also maybe Froome being a natural, even freakish, athlete) that other teams have not fully exploited.
I don't want to jump to an assumption of doping, and I want to believe the Sky marginal gains mantra, but I'm finding it difficult. I'm looking for something to explain just how it is that Froome can leave other riders going backwards.