I think the test is that new sign-ups won't have it and will the loss of five new Pro subscriptions be offset by more than one new Max subscribers.

Plenty of Pro subscribers never touch claude-code.

That's how i read it too - they want to test if people will still pay for pro plan if it doesn't include Claude Code. At the same time they are also saying that if you subscribe having been told it does include Claude Code, they may still change their mind later and take it away!