You who registered in 2013 surely lived through the first few years of quality posts but the merit system was introduced in January 2018 to deal with the spam problem that did not come overnight. As of today we are better in terms of overall quality posts than in 2017 and basically today practically only casinos are advertised.
Yes, I think merit has improved the situation a bit. But I think there is plenty of air to the upside still. And even a little visual upgrade, a slightly more attractive CSS theme for example and better mobile usability, could already help, because it would make good forum threads "shareable" on other social media as I already wrote in another post. This would make it possible to reach out for both forum and social media audiences.
Of course the mixer ban has contributed to the reduction of campaigns. But I remember mixers weren't
that active in campaigns until 3-4 years ago. There were always a few mixers but most of the campaigns were always run by casinos and ICOs, in the early years of the campaign boom (around 2016/2017) also altcoin projects like Waves were quite active. ICOs have past their hype and are also more heavily regulated now, so it's not surprising there are only few ICO campaigns left. But in general casinos almost always made up 50% or more of the active campaigns. So I don't see that big of a difference to the olden times.
In general privacy-respecting services which are not classic mixers (and thus are not banned, but which could have problems to advertise on the big platforms) should do well here. Perhaps also smaller campaigns with 2-3 slots could be an option.