1212
This is of course not including the yearly Unity subscription, where Unity Pro costs $2,040 per seat (although they may have Enterprise pricing)
Absolutely ridiculous. Many Unity devs are saying they're switching engines on social media.
Developing a good and feature rich game engine which also runs performant is a huge effort. That alone can cost a good team 2 years at least. Even more if we consider todays graphic standards. That's nothing which smaller studios can easily deliver. So yeah, it's an obvious decision to buy a license for a proprietary engine, where a lot of work has already went into. That's just business and nothing crazy about it. Companies using services or products of other companies is pretty ordinary.
FOSS alternatives to Unity exist though. And from my personal experience it looks like Godot seems like the better engine anyways. Not to mention the fact that there is no need for a game engine to create a game. Opengl + a windowing/utility library is ideal.