In reply to AlanLittle:
> ... exceptionally high VO2Max doesn't appear to be one of the necessary attributes of a top alpinist.
Oh, no doubt, I'm not arguing with you. The very term 'top alpinist' is quite subjective and lab measurements are only fractionally relevant at best.
Alpinism is still very amateurish compared to other sports, though some people are trying to change that by devising and marketing mountain-focused training programs. It's one of the few ways to make any real money out of climbing, more to the point here.
Jornet and Steck have spent some time together and Steck is on record somewhere (that I can't be bothered finding) implying that if Jornet had Steck's climbing skill he would be phenomenal. Traditionally those with the very highest genetic physiological traits - very high VO2max, vertical jump, leg speed etc - have been sucked into other, more lucrative, sports, never getting near climbing. That might change in the future. Having the combination of genetic traits, physical training, nutrition control, mental drive, technical skill and western leisure society benefits is something we haven't really seen yet. Alex Lowe probably came closest in recent times, and Steck is probably closer still.
There is a burgeoning field of training for training's sake, or just competing in training (CrossFit, Tough Mudder, etc). GymJones was meant to be training for a purpose, but I'm not sure that has eventuated.
There are so many aspects governing success on big alpine objectives, physical fitness - underrated by some, overrated by others - is just one of them. There's a hell of a lot of hyped up training going on nowadays, but I'm yet to see the commensurate explosion in big, hard Himalayan alpine-style first ascents (those being a traditional, if slightly narrow, yardstick of achievement).