FWIW, the videos with sponsored content are frequently either not getting money from YouTube (such as the gaming segment), or not getting enough from the ads that do run (COPA affected and . The creators may also be futureproofing their livelyhood in fear that their segment will be the next one that YouTube demonitizes by default.
It’s not very profitable to be a content maker (outside the top .01%), and many content creators are paying a team to help them produce regular, high quality videos.