I get that people do it for passion, I enjoy sharing knowledge too, and in an ideal world where I didn't have to earn money, I'd be doing it along with everyone else as part of a great virtuous cycle.
However, the current situation is mostly at odds with making a career out of education. I really can't invest as much time as I'd like into educational work because I have a family to support, and I barely break even on the hours invested.
It means that trying any new interesting approaches is out of the question, and advanced topics with a smaller audience are unlikely to see the light of day, which is a pity.
But I guess as long as there is a supply of people willing to do this kind of work on top of a regular job, the situation will only become more entrenched.