It's also already the case that in larger companies people do not have access to these plans as employees and must use API rates.
There's also the political angle. When Anthropic and OpenAI held back their top of the line models because of Bessent & Trump's bullshit, and threatened to deny unwashed foreigners like me access... I dropped my Codex plan and made do purely with GLM 5.2 for three weeks before OpenAI finally released 5.6 Sol. Feels inevitable that this will happen again.
Or, somebody will come up with a way to serve e.g. Kimi K3 or the new Qwen model in an extremely cheap way. Or DeepSeek releases a competitive model at their cut-throat rates. And then the cost argument just wins.