You dont lose your title. You end up suffering the ravages of old age, but you dont lose your title.
Can a Titled Player Lose Their Title?

If you could lose your PhD for becoming a moron, America would be facing a serious shortage of college professors.
Lol, good one.

Well, if you are a GM, but you are only invited to very mediocre FIDE rated tournaments with elo average 2300 or lower your rating will go down. and also your motivation and quality of your game no matter how much you try. I am not saying this is the case of every low rated GM though.

I mean probably, I don't know about a GRANDMASTER that ain't no master tier player... Sorry, but that's sillyish!
GM Bisguier earned his GM title in 1957, and was back down to 2170 FIDE by 2014.
"GM Bisguier earned his GM title in 1957, and was back down to 2170 FIDE by 2014."
When he was 85! Bisguier loved chess and didn't give a rat's ass about his rating.
"Kind of funny how you, yourself mentioned black but nobody else did. I could've been talking about green leprechauns"
But you weren't, and everyone knows it. Why pretend? Own it!

Just like you don't lose your PhD/Dr. title if you get Alzheimer's and can't pass an exam in your field.
but they can take the PhD away from you if they discover you did plagiarism!

In the late 1960s and early 1970s they experimented with activity requirements for titled players (back then it was only IMs and GMs): simply put, in order to retain their title, they had to produce performances commensurate with the requirements for gaining the title over a specific period of time (something like 2-3 years). They abandoned it presumably because it became rather complex to police, even with the relatively low number of titled players at the time, and also very cumbersome for norm seekers; players could be stripped of their norm just ahead of a tournament, meaning that the tournament no longer fulfilled the norm critieria for non-titled players. Also, once they introduced the Elo system, it became rather unnecessary.

In fairness to the person Damonevic is talking about:
There's nothing suspicious or dodgy about his title or ranking. It's not as though he was some patzer who had a lucky run, or someone who bribes his way to wins. He was a very highly ranked IM for years, and then he beat GM Kosyrev, he beat GM Friedel etc. He didn't find the GM status in a box of Wheaties, he earned it.
hypothetically lets say a GM all of a sudden contracted some memory illness and started playing at a 1200 rated level (or something far below what a GM should play at). is it possible to lose the title once achieved? if no, why not? wouldn't having really weak GMs, IMs, FMs and NMs degrade the value of the title in chess?