I suspect a lot of people wouldn't use AI if they had to pay per token at current rates. Yes, it's technically a different discussion, but "just write your own harness" isn't really an answer for the vast majority of us riding on the investor-subsidized subscription plans.
I did, and the weird things you have to do to make work at least decent. I’ve been doing evals and I got some things better than opencode but not as good as pi. Though my goal is to optimize for a browser and browser based llm so it can create stuff in a web container or at least generate ui by requesting json schema (a2ui style).