Just because the manager counts a post and the moderator doesn't delete it doesn't mean the post is actually good. Most of the time, our reports go unhandled because there are so many of them. Additionally, some managers use Ninjasty.space to count posts without properly evaluating the posts' quality as long as the user met the weekly post requirement.
Some of the best campaigns simply don't pay for the posts made after a certain page of a megathread. Of course, it depends also on what's the thread about and the quality of the post.
Also, of course that in many cases the campaign/bounty managers could do better if they would care about the forum. On the other hand, the advertiser wants visibility and some don't care where that visibility is, so the managers will also just do the counting and that's all.
Of course, in altcoin announcements I've often seen threads very long and filled with spam. In some cases they were even paying for that spam to keep their topic look alive. But I still feel like restricting topics' length will do nothing good.
For now I still think that the only solution is to report the spam.
I'm not sure i missed that 
Sorry, but then I don't think that the poll holds any value. It will only tell whether there are people somewhat sharing your view, but no information at all about the rest.