It's just one of those things that should never change

no

He actually did give up his blanket later on in the comic strips. Like in the 1990s when Schultz retired from making Peanuts.

when linus gives but his blanket, it'll be the start to the end of the world

Anything's possible

NO WAY! Just because Schultz retired from making Peanuts(Which upset me), doesn't mean Linus gives up His blanket in my book! His blanket is the thing that separates Him from the others, so He can't get rid of it! He just CAN'T!

Linus and his blanket are like peanut butter and jelly. Always together. ;)

NEVER

Linus did give up his blanket in the comic strip, but only when the reader was looking ;) He probably had it out when the newspaper was closed ;) ;)
Besides, the new Peanuts special they're making is called "Happiness is a Warm Blanket, Charlie Brown" so they obviously don't think he should get rid of it.

Sometimes Lucy just hide his blanket.

He has actually lost it and/or given it up on a few occasions, but something always happens and he ends up being hooked again!

I think this might be one of the reasons why Schulz left it in his will that no one was allowed to continue the comic strip. He probably didn't want people changing certain running gags about the characters (e.g. Linus with his blanket, Schroeder with his piano, Lucy with her obsession over Schroeder and Charlie Brown never winning a baseball game).

The characters never canonically grew up, but if they had, I can imagine Linus ending up still keeping his blanket in some way or another! Like in the comic strips where he finds other uses for it (like swatting a fly, or whipping an apple off of a tree) I can imagine him being creative with its uses as an adult! XD