The thing is there's no money in charging writers, really. There's just not enough of them, and they aren't going to pay you enough (certainly not to reach golden egg territory). You must monetize on a per reader basis if you want real revenue.

There is a market but how big, I'd assume that these are real offers

https://wordpress.com/pricing/?compare=1#lpc-pricing

that seem like what somebody would pay. If you'd assume somebody spends 4 hours a week blogging and their time is worth $25 an hour you'd be putting $400 of hour of labor in a month and spending $40 for hosting is a fraction of that. That $25/hour would seem low to some people but high to others: some people are time-rich and cash-poor and others the other way around.

The horrific truth about the "Next Medium" is that it is going to appeal to people who are too lazy to write a successful blog by having GPT-4 write their blog posts for them.