> "we just removed some features so we could charge you for them"
I think the pitch would be more like "we want to focus our more limited resources toward ensuring the core of the product is as good as possible, and there isn't a way to continue shipping an unmaintained version of the UI, so we haven't brought that part of MinIO into the community version of <new product name XX>. By offering it as a paid option, we hope to be able to sustainably maintain both the open and closed parts of XX over the long term."
I mean look, whether it makes sense or not, the proposition is you pay for the privilege of using things you already had for free so that you can help someone else bootstrap a sustainable business off of something (something that they didn't even make in that case, for what it's worth.) If there was a Linux Foundation fork, I'm pretty sure it would win out rather quickly.
With open source, I think what companies really want is an open source project that is maintained by people with stakes in the project, but complementary ones rather than primary. Helping pay for a new business seems like a worse proposition than just getting some major stakeholders to donate a headcount or two; yeah, it's expensive, but it's probably a better status quo and should nearly indefinitely cut out any concerns about rent seeking behavior.
I think the pitch would be more like "we want to focus our more limited resources toward ensuring the core of the product is as good as possible, and there isn't a way to continue shipping an unmaintained version of the UI, so we haven't brought that part of MinIO into the community version of <new product name XX>. By offering it as a paid option, we hope to be able to sustainably maintain both the open and closed parts of XX over the long term."