It's wonderful when someone is able to constructively do something on the forum instead of continuing with whatever they were expected to do under the status quo. Enabling that sort of thing is exactly why Bitcoin and this forum were created. Though bitcointalk.org is not a worldwide welfare organization, and people are not entitled to make money.
Limiting newbie participation is very harmful for a community. Newbie jail will never return: I consider the newbie-jail period to have been extremely damaging to the forum. When barriers to participation are too high, then the best people often just won't go to the trouble of joining, and the people who are willing to jump through the hoops are often people who aren't good for the community: people with nothing better to do, scammers, get-rick-quickers, etc. Having a permanent newbie jail policy would improve things a lot in the short-term, but would end up being a fatal poison to the community.
The low signal-to-noise is a real issue which seriously annoys me and is often on my mind. But as you mention, fixing it non-destructively is difficult.
Thing is, this is the internet, spam rules over everything else. Only way to combat spam is to have very strict moderation, have mods patrolling through 24/7 and that also doesn't guarantee that there'd be no spam. People are selling services like ANN bumping, hacked accounts, autoreply bots off-forum, and it makes it much harder for the forum to know who uses these. When cloudfare was integrated, the bots that mods used to use became obsolete, so we thought that might be the end of bots, but we were wrong. Cloudfare doesn't block the bots that only spams.
But what is the role of the campaign manager then? If they accept such users in campaigns then nothing can be done to stop them from shitposting. Hence both the manager and the mods of the forum need to monitor them for such shitposting spree.
Literally speaking once they spam - they will eventually get banned and then make another account - by whatever method and start a new journey on bitcointalk. That is where merit stops them from ranking up and the same thing repeats. Ultimately they will get tired and frustrated and then leave the forum.
And spammers never get frustrated. They come up with something , always. One or two might give up, but there are hundreds of thousands of them that are still left.
About campaign managers allowing shitposters, they aren't campaign mangers. They don't deserve that title. Its about time, that theymos gives a guideline on how to manage campaigns/bounties.