"Is it a possible that Anand is just a very very weak GM"
No.
Chess is not a young man's game, it is a wonderful game that a person of any age can play, unlike more physical activities which demand youth in oder to be capable of partaking. I will agree that a younger person (not necessarily man) will compete more successfully at the highest level. Let us not be sexist or ageist. I am 58 and I love playing chess (younger members of our club do tend to beat me though)
Everybody's rating is inflated.