Then why are they stopping people from having multiple max plans? If they are making such good margins on inference.
They are likely aiming to maximize reach/mindshare. Get as many people hooked as possible. More important than minor upside from a few multi-Max users.
EDIT: also, the casual or gym-style members that pay every month but barely use the service are of course very valuable wrt margins
They have good margins on inference at API costs, i.e. $5/$25 per mtok input/output. They are almost certainly making losses on subscriptions, at least if people max out rate limits.
In the past 30 days I have burned $78.19 in API token costs with my $20/month Claude Pro subscription. In January I burnt over $300 in API token costs.