Indeed. But as I've always said, just because someone is motivated by money to post, it doesn't mean that person's posts have to be garbage. Look at the Chipmixer campaign (and *ahem* Foxpup's exclusive Merit Cycling Club); only members who know how to write and/or attract attention get into campaigns like that, and to be accepted you have to have an established history of making quality posts. Sadly, a lot of other campaigns have much lower standards, and most token-paying bounties have almost no standards whatsoever.
Come to think of it, does every member get paid handsomely to join the campaign? I recalled Loyce's getting paid quite a sum every week based on some posts made by Foxpup, but that's all I know of.
For ChipMixer, that's the "laziest" campaign I ever come across that almost has near-zero chances to join. These two are one of a kind :p
If those campaign managers were to raise the bar, I reckon we'd see a handful of campaigns surviving for a few weeks tops. But after all, advertising has always been a mixed bag. You come across good posters as well as bad ones. As long as the advertisers gain the exposure and new clients, the posts quality don't really matter. Just like how spam works.