Can A GM Title Be withdrawn?

Is it possible that a Grandmaster plays horrible chess and drops to very low ratings then can  his title be taken away?

No, it is a life title.

In fact I think all FIDE titles are for life.

It happened once to some Romanian player who scored like 0,5/9 in a tournament and failed to solve a very common endgame theme. His name is Alexandru Crisan.

Also Nigalidze saw his title stripped for cheating: https://en.chessbase.com/post/nigalidze-stripped-of-gm-title-receives-3-year-ban

Alexandru Crisan falsified reports of tournaments to get a nice 2635 rating, they used those tournaments to see if he was really that strenght or not.

Yup.

So I think if you win your title cleanly you can perform like crap later on and still have it. 

well, job security like of thing then!

So the majority of GMs are not at GM level anymore, they just got there once in their youth for an indeterminate amount of time

A GM does not have to maintain a >2500 FIDE rating to remain a GM. However, there have been at least two instances of GMs being stripped of their titles as punishment for cheating. Igor Rausis was probably the most famous example; when he died in 2024 after a very long battle with cancer, reactions to his death were quite mixed due to the cheating scandal that derailed his career in 2019.