The problem is they now want to license the engine as a separate product which they didn’t do in the past. Previously, you paid your license fee for editor and any game you build off that is deployed and you could stop paying them.

I guess they didn’t like the thought of not being able to perpetually milk their customers and wanted to increase their cut outside of the editor fee.

From what I understand though, Unreal is just licensed based on revenue and all the editing tools are free. Unity had the opposite approach previously. They’ve decided they want a cut of both pies.

This has nothing to do with whether there are perpetual licenses or not.

The way the go about this makes it seem that you enter a contract that you can never reasonably exit out of, as in order for you to stop having to pay, you'd have to convincingly prove that you forced every customer to uninstall your app, i.e. that there isn't at least one install left.

This sounds absolutely bonkers to me.