I was watching a documentary on Fouseytube last night. At the tail end of the prank video era (2016) he was making less than $500 although he had a 2m viewers who watched his prank video. A few years before he was generating thousands per video. A -95% drop in profits. This is why many YouTube creators now have multiple streams of income. Many are now streaming on TikTok, and Twitch. Especially Twitch with donations, ad revenue, etc. It can be very profitable if you can pull it off. Many also sell merch. I doubt that most are making a lot off that though. Selling courses is another huge revenue stream for many of these guys. Many of these courses that YT creators make sell for $995 each. There are also courses that go for $1995 each. You sell 2-5 courses per day. That is a lot of money.
Must have been getting hit with age restrictions and no ad money. I have seen youtubers with middling subscriber numbers that can make $39k on one vid. No, leaving youtube is a huge risk for most established content creators. It is their livelihoods at stake. And while many whinge about all things youtube, they don't complain about cashing those fat checks. Hell, 99% of the whinging is about not getting what they think they deserve.
You are right that it is smart not to keep all their eggs in one basket. They should be exploring every platform, and developing content for it if they have the ability, won't hurt their brand. Ventures like Floatplane and Nebula are always welcome. Pod casting is smart. But those numbers I linked speak for themselves. There is nothing for the end user with an ad blocker to complain about really. Free content, and more than you can hope to watch in one lifetime. If the fantasy is that fans are going to white knight creators that are butt hurt and follow them elsewhere, they are in for a terrible disappointment. Remember in the Truman Show how the world was enthralled with him, and 30 seconds after he left the building, the guy is asking his buddy what else is on? That's what happens IRL. People have short attention spans and seek instant gratification, If the youtuber leaves, most will just find someone else to watch that makes similar content. Remember when Ninja got crazy money to go to Mixer? How'd that work out for the service? I know that was Twitch v. Mixer, but Youtube is to content creators what Twitch is to streamers. Both are nearly impossible to unseat. It may happen someday, but the idea that it will be soon? I will bet money against it, and I don't gamble.