It's not a perfect analogy, but none-the-less, Schumi's physical fitness was still better than most drivers on the grid; he spent around 5 hours a day in the gym. Reaction time has been proven not to change with age (and surprisingly, it's been demonstrated that reaction time for racing car drivers isn't any faster than most people; the difference is in the "muscle memory" ... ie "knowing exactly what to do when a reaction is called for, without having to think about it). And stamina actually improves around that age (look at the age of the top marathon runners).
No argument there.Adams' encroaching age did not deteriorate his talent; if anything, his maturity made him even better. It was his innate ability to "see", or as someone else said either here or on another site, to visualize the printed image before he even set up his gear, that made him great.
No argument there either.Thus, in his hands, the improved technology we enjoy today would have made his shots even better today than they were.
I would say that he would be able to produce better images today than he could with the technology available to him in his day (much as Juan Manual Fangio would lap a track faster in a modern technology car faster than he could in cars of his generation), but I don't think it holds true to say "his superior vision over his peers in his hey day necessarily means he would enjoy the same advantage over present day photographers"; I think it's most likely that many modern-day photographers have equal if not a superior ability to "see the light".I do not mean to say that the best photographers of today are deficient in any way, just that Adams would be better - because of his superior ability to see.