Their subscriptions aren't cheap, and it has nothing really to do with them controlling the system.

It's just price differentiation - they know consumers are price sensitive, and that companies wanting to use their APIs to build products so they can slap AI on their portfolio and get access to AI-related investor money can be milked. On the consumer-facing front, they live off branding and if you're not using claude code, you might not associate the tool with Anthropic, which means losing publicity that drives API sales.