The problem is that Microsoft wants to pay that for a permanent “never maintain in a way that breaks caption decoding in any default behaviour we use” with that one time payment.
Its a quick fix on Microsofts end to change a quick flag in ffmpeg. It’s also quick on their end to maintain a fork that only changes the default. One time payments for maintenance make open source projects like ffmpeg subject to fail.

There’s a piece of software that I use at work for managing tickets for a client, every time I open it there’s a note that the app will be replaced next month on the 1st. This notice gets updated on the 27th of each month without fail by the end of day. For now critical infrastructure remains running on a windows xp machine that we remote into using the only software that let’s people connect to it.