Age of chess players

Is there a trend, that when best of the chess players in the world goes older, they lose their abilyties, they stop going to tournaments, they are weak than the best players which are younger? What is the problem with the old one... they can't remember combinations, or they can't concentrate? 

To bad youth is wasted on the Young!

I'm 80

DENVER

There is another! Practically, physical strength and training as a whole is very important, when you go to a tournament... There practically you play very often against opponents, who are equal in chess to you. It is very important to withstand the load. You have to be concentrated for 4-5-8 hours. Only solid physical training can help you do it. That is exactly, why chess is called sport...

When we grow old, we lose our strength and the ability to withstand the load.

That is why world champions will always be young people...

There is in addition to this one very practical element that is age related.  As you get older your responsibilities increase and your priorities and likewise time, effort and attention need to be divided to meet those increased responsibilities and priorities ( getting married, starting a family, raising and being there for your children/spouse ( which not only includes time around them but spending quality time with them, their interests, family outings and events, school/helping with school work, spending non parent time with your spouse etc  ).  ).  It is important to understand that even if all things were equal and a player did not age beyond 20, the requirement needed to adequately take on and progress the average endeavours the average persons pursues as they progress in life means that you necessarily need to split/reduce the time you once previously had to devote almost exclusively to maintaining and getting better at chess.