He doesn't do it to make any money. He says that the small fee entirely eliminated trolls, and almost entirely eliminated people who join for week 1 and never return.
Show me a thing that has not been defiled by opening it wide to the horror that is the average intelligence. Twitter and Facebook is a dumpster fire, ultimately destroying political discourse and locking almost half of the population in a dangerous alternate reality. They now turned violent and will continue to do so.
Masses of hodlers are now destabilizing markets with their GME raids and crypto.
Etc...
Not to criticize that possible solution, as I also agree with it in principle, but it is probably much harder to implement well than it looks, and should be created from scratch with scalability in mind: micropayments per post probably are the best option, which if applied to email too would eliminate spam in seconds, although that would also sound like admitting the defeat of the Internet as we knew it.
I mean, I totally understand where you're coming from because it is very different from the current model where almost everything is free.
But at the end of the day if you're not willing to pay $100/month (which is less than many people pay for cable TV!) then maybe you don't really want to comment on that 100 blogs all that much