I would imagine any medical app/ERP/etc. would have creative ways to get users to not make a one-time purchase via the Apple. Although certain interpretations of the rules might mean they have to offer App Store signup as an option.

Yeah apps for pilots also came to mind, though I took a look and ForeFlight was $400/year on the iOS store, not a one-time fee.

Why charge $1000 once when you can charge $400 six times?

I refuse to use apps like this. None of my Apple IDs have payment information associated with them.

I’m not aware of many apps like those that aren’t done via a B2B licensing agreement outside of the App Store.

Early on, I remember there being a tactic for apps where the owner wants them to be findable in the App Store, but doesn't want any new buyers, they set the price to $10K. But these days, I think the most expensive apps are $1K - app.cash, vueCAD Pro and Cyber Tuner.