> 1) Anthropic doesn't want their subsidised plans being used outside of CC, which would imply that the money their making off it isn't enough, a

Claude Code use-cases also differ somewhat from general API use, where the former is engineered for high cache utilization. We know from overall API costs (both Anthropic and OpenRouter) that cached inputs cost an order of magnitude less than uncached inputs, but OpenCode/pi/OpenClaw don't necessarily have the same kind of aggressive cache-use optimizations.

Vertically integrated stacks might also be able to have a first layer of globally shared KV cache for the system prompts, if the preamble is not user specific and changes rarely.

> 2) last time I checked, API spending is capped at $5000 a month

Per https://platform.claude.com/docs/en/api/rate-limits, that seems to only be true for general credit-funded accounts. If you contact Anthropic's sales team and set up monthly invoicing, there's evidently no fixed spending limit.