The cost to find a spam-resistant email address is non-trivial. Even if someone who's only making $6/hour can find two a minute, that's still $0.05 each. Even if they do ten a minute, that's $0.01 each.
How is anybody who is engaged in such a practice going to come anywhere near breaking even? To be sure, spammers exchange lists a lot, so a person who's gif-cloaked email address gets found out once will receive spam from all over, but how does that benefit the person who found it first?
As noted, the only thing I can figure is either that the person who's going through the trouble of listing such addresses expects to make money selling lists of "Addresses not found on any other list!!!!!!!!" or else views the annoyance of the addressee as being a meaningful objective in and of itself.
And then when you want to send spam, all you need is a list of addresses and an smtp server.
Or is there more to it and I just don't realize it?