If a 31-32 Jon Jones can struggle to keep Dominic Reyes or Thiago Santos down...
Then it is certain not inconceivable that a 37 or 38 year old Jon Jones could struggle to keep Alex Pereira down.
Jon and Alex are the same age... but it has USUALLY (Hendo, DC, Stipe, Weidman, Romero, Rampage, Aldo, Frankie...) been the pattern that MMA fighters tend to gravitate AWAY from wrestling heavy approaches as they get older due to the taxing, cardio draining nature of wrestling and the likelihood that accumulated injuries over the years tend to cause more issues with grappling than with striking.
I don't think this fight ever happens.
If it does, which presumably means both men can get past Ankalaev and Aspinal respectively,
Alex has more of a chance than most people are giving him.