One question I would like to ask is if mixer campaigns are banned from this bitcoin talk forum will mixers stop? Of course they will try to advertise in other places. If the mixer doesn't stop, it might be better to let the campaign go on this forum.
Unlikely, there are plenty of advertising platforms to advertise any product.
Then the first few pages will be full of old mixer ANNs which I don't think is the behavior you intended.
I don't think this mess in the archive will stay for long. After few weeks those topics will have a place on other pages than the first page.