I am a paying IHP user, working on it commercially, and I for one support the paid plan.

If I used it for pure hobby, the paid version features wouldn't really matter that much to me anyway, but professionally these are timesavers.

I always get help, and I don't feel bad asking for support. I get listened to when suggesting improvements, and many times they do the job of implementing well thought out suggestions.

It's not purely based on devs working on it on their free time (although some do that as well). The core maintainers have a real incentive to keep the framework going strong.

The paid features are stuff like third-party oauth and Stripe, and does not bring limitations on the framework itself.

So that's some arguments, although biased, by being a fan of the framework :)