The bounty managers are paid anyway. Their payment doesn't depend on the quality of the posts of the participants.
If they are lazy enough, they won't care about the post quality...
If those who advertise with the signature campaign would differentiate the payment of the manager based on the post quality, that would be a motivation for the bounty manager to care about quality too.
But, unfortunately those who advertise with the bounty managers, also don't care about quality, just quantity....
Wouldn't this require the advertiser to check post quality too, though? Kind of defeating the point of having a campaign manager "manage" the campaign. Well, I guess they still send out payments, but I'm sure if the advertiser is willing to check every single post then they would be willing to send out the payments too, and save themselves some money in hiring a campaign manager.