For some players everything is possible and indeed only a handful of people can do this and Benzema is one of them now.
Age is just a number really happened but most likely this only happened once for him. Even though this season there are still the same opportunities but seeing the condition of some of the current young players who are quite good I seem a little doubtful that Benzema can do this again.
His only disadvantage is the fact that he is not young anymore, obviously Messi and Ronaldo won so many times, since 2008 only Modric won it once in 2018 and for the first time after that it's Benzma, only 2 players managed to win this outside of Ronaldo and Messi for the past 14 years, that’s a big achievement.
Nobody should expect players to win it more than once, yes messi and ronaldo did it multiple times, but usually that’s not that easy, players don't have "best ever football player of the year" levels of performance each year, that’s rare. I believe that Mbappe and Haaland could be the only players actively playing that may end up getting more than one.