I reckon Messi's career would have been over a couple of years ago had he played when Maradona did. Maradona was physically a lot more robust than Messi, and I am convinced it helped him to bounce back more than once from the assaults he was subjected to.
There is one thing not mentioned here either. You had to be quite a bit braver playing the way Messi and Maradona are famous for in Maradona's time. Messi can go on his runs knowing that he is quite well protected by the ref and the modern laws of the game. Maradona did the same thing, but knowing he could be on the wrong end of a horrendous tackle at any given time. He very often was too.