But are they profitable?

That's generally what "making money" means. Profit, not revenue.

Based on API pricing per tokens, I'm getting anywhere from $10-20k/month in surplus value from a single $200 subscription.

How are they making money in your view?

By selling subscription tokens for less than they cost to generate, of course.

What you said doesn't yield any information whatsoever about whether or not subscriptions are profitable, all that says is that subscriptions are less profitable than API.

Things are able to be less profitable than other things while still being profitable.

If something like the API is very very profitable, it's even possible for profitable things to be much less profitable!