Hey Josh,
The changes won't break your app, it will still work fine ... but you will lose the Premium styling feature that we have been giving away for free until now.
Customers of Moodle Partners or MoodleCloud will get Premium for free, including this CSS styling feature.
We would love you to contribute to Moodle, yes, either by paying for a Premium app (it's a low cost in the scheme of things) or by moving away from LTG to one of our many Moodle Partners.
(As you pointed out, so-called OpenLMS are not a Partner, do not contribute anything to Moodle, and I can tell you, won't ever be (despite anything they may tell you), so I would very much encourage you to move away from them if you are able - contact me direct if you want to discuss it or need help.)
No-one likes to pay for services, but we must - that's how the economy works. Over 90% of Moodle-using institutions do not contribute anything back to Moodle, this change to one of our services is designed to make it easier for everyone to choose to support the truly open source software they use, and to help us make it better and better for you.
Best regards,
Martin from Moodle