While the subscription is definitely subsidized (technically cross-subsidized, because the subsidy is coming from users who pay but barely use it), Claude Code also does a ton of prompt caching that reduces LLM dependency. I have done many hours-long coding sessions and built entire websites using the latest Opus and the final tally came to like $4, whereas without caching it would have been $25-30.

Are you saying CC does caching that opencode does not? What does Anthropic care? They limit you based on tokens, so if other agents burn more then users will simply get less work done, not use more tokens, which they can't. I don't think Anthropic's objection is technical.