There is not really anywhere for the creators to go so they don’t really have any leverage. If you’re mad at YouTube you can go to an alternative and get 100-1000x less traffic and revenue. And some other obnoxious creator will take your spot on YouTube immediately
You would need a mass exodus of top YouTube creators to make the slightest dent on YouTube's bottom line. Meanwhile, any top YouTube creator leaving YouTube (to what alternative?) isn't hurting his or her bottom line, but rather nuking it from orbit.
In that case the effect on YouTube's bottom line would be even smaller, if any. Creators posting their videos on other platforms would have a negligible to no effect on YouTube, given that it would remain the default (read "only") video platform for the overwhelming majority of the viewing public. A creator announcing "You may also see my videos on DailyMotion/Vimeo/Twitch/PeerTube/wherever" would simply be irrelevant to their mass audience, who would react anywhere between "Ok, whatever" to "I don't know what that means, ignore".
The only reason I can think of is so they can keep up their "we need to police bad actors" image necessary to maintain the moral high ground when they mistreat creators for the sake of sanitizing their platform.
Hold YouTube responsible for the content of their advertising. If they advertise scams and people end up scammed, IMO, they should be held legally culpable for that. They played a role that they were paid for.