I think people who don't make videos for a living severely underestimate how expensive it is to produce high-quality videos people want to watch. This isn't like writing a tweet or even posting a picture on Instagram. Even a decent 20-minute video can easily take 40 man-hours of high-skilled labor.
I have a pretty small channel (~100K subscribers) with no employees and relatively low upkeep costs (a few hundred dollars a month), and even I could not make this work if I didn't get at least $500-$1,000 per video on average, since it just takes so much time and money.
Most channels with more than a million subscribers are likely founders working 60-80 hour weeks with multiple full-time employees supporting them. You cannot do that in the hopes of viewers donating $5 here and there.
And yes, there are people who make content for free - most of them fail to hit a hundred views per video. And the difference between a million views and a hundred is 10,000x. You cannot create a platform without big users.
I think any real competitor to YouTube nowadays would have to be backed by a big corporation that can pay big creators million-dollar deals to make the switch. Otherwise it's just dead in the water.