Bernard Shaw hated the apostrophe, and used to insist his writing were printed without it. I suspect that in fact he didn't actually care much, but enjoyed teasing people who get passionate about this kind of thing.

I suspect that the grocer's apostrophe - "Apple's 50p" - is often intentional. It attracts the attention of pedantic passers by, who may then may possibly make a purchase.

"The world would be a much safer place if the possessive apostrophe were abolished completely." Yeah, it's really very dangerous isn't it? It could put your eye out if you aren't careful...

"It adds no information," If correctly placed it does in fact provide extra information. For example, "the girl's room" means something different from "the girls' room".