[dietrichepp]

I wouldn't say "completely defeats". The hacks are usually there only when you need to manage the lifetime of something that's not managed by the garbage collector. I've seen it used for mutexes, for example, to keep a mutex alive and locked.

You could say that the problem is that people abuse the garbage collector to manage something it shouldn't manage, or you could say that the problem is that garbage collectors are bad at managing anything that isn't memory. (I would lean towards the latter.)