It's not just the platforms; many advertising-supported sites are in crisis for reasons I don't completely understand.
The symptom I've seen is that many sites I've followed for years (e.g arstechnica, anandtech, audioholics, just to start with "a") have (in the last 4 months) gone to a reduced production rate, started running junk sponsored articles, and have dropped quality.
Some inputs are: ad blockers, ad blocker blockers, anti-tracking on the part of Apple and others, skepticism over click fraud, increased conflict in the "supply chain", drop in screen time now that we're in the eye of the covid storm, etc.
