Developers who have been using unity with knowledge of their pricing mechanisms are being blindsided with new pricing

I get that, and it sucks. But too many offerings on the market are nowadays accepted as normal operating procedure, when they seem like such obvious traps to me. There is no financially-driven company out there that you can rely on with your project. Go with an open-source project or write what you need yourself. I fully understand the challenge of writing a product from scratch and bringing it to market. Your dependencies can break your neck one way or the other.

You can’t just move to a different platform without significant amounts of rework.

I know and feel that. I am no longer in entertainment, but I also see these exact same patterns in my current line of work (IT infrastructure). People use "free" tools that they take for granted, and then they're surprised by rug-pulls. This has been happening for so long in so many areas that it's almost tiring.