Fair enough but in that case it might have been better to post examples of these confirmable "real" alternate futures, instead of the very specific fake one. Especialy since that one excludes factors that would have prevented some of other X-men besides "element form" Storm and Iceman from heavily aging either like Gambit's energy controll (in one alternate world he became an immortal energy being), Beast's superhuman metabolism, Marrow's healing factor (see Sabertooth, Wolverine and co. for how she should look in 50 years) or Collosus metal form.
All which could come into play if a writer would want to depict them still alive and kicking 50 or 100 years from now.
Otherwise a simulation of Arcade in which he beats Wolverine in hand to hand combat and Storm totaly is into his toy collection would count as proof of possibility too (joking of course).