I think "offer unlimited but TOS ban behaviors that would cost too much to support" is actually a very normal way that things work instead of "raise prices until equilibrium is reached", including in credit cards. Credit cards do simply ban people they think are "rewards churning" based on a completely subjective TOS policy for example.

Raising prices is a bad strategy if you have a smaller base that costs enormously larger than the rest. "A million users that cost $1 and one user that costs $10 million, charge everyone $10 equilibrium", you're screwing over almost all of your users. The $20/month sub price is basically just not trying to capture the openclaw users, it doesn't make sense that all of the vanilla Claude users should subsidize them (and in fact it wouldn't even work because they will just go to Gemini or ChatGPT if your cheapest paid plan was very expensive to try to subsidize the other users)