1) Quite a bit. Regardless of what format you play, if you're playing competitively, you're making an investment. 2) I don't follow the meta-game much anymore, but blocks and core sets cycle faster than you'd like sometimes (in standard at least), leading to the scenarios you mentioned. 3) I have no idea. 4) Yes. I've collected other card games in the past, but I've yet to come across one that does art and lore as well as Magic. If that's not your thing, well, buy some anyways. It's a great system, and it has some flaws, but what doesn't?
The only reason people seem less retarded in the forums is because they don't have as much pressure to spew their garbage. With slightly more time to think through what they're posting, a small degree of eloquence is achievable.
Holy shit, don't get me fucking started on those self-professed Juggalos that ingest ICP and that "culture" as a way of life. I swear to christ: knowing these people exist and act in a completely non-ironic state is goddamn disturbing in the truest sense of the word. Gas the whole motherfucking lot of 'em.