Perhaps you should reread that letter:
However, many of us are frustrated. Those of us who run some of the most popular projects on GitHub feel completely ignored by you. We’ve gone through the only support channel that you have given us either to receive an empty response or even no response at all. We have no visibility into what has happened with our requests, or whether GitHub is working on them.
Or in other words, to answer the question I was asked (which was "Did they who filed the letter ask?"), yes, they did ask. Apparently repeatedly.
That said, they set the bar pretty high, and now they need to execute.
Well, if they truly have "more imporant things to do than address community ire", then this also means that they agree to take the community's ire.
That's no way to run a modern web-based business for alpha geeks.
When I get feedback, especially negative, I like to think about it before I respond. And I may take a month to respond.
But I always immediately respond with something like
"Thank you for providing feedback, and thanks for your patience while I think about your feedback, discuss it, and respond appropriately."
At least you then know I'm not ignoring it.
I have no insight into their internals, but, IME, getting that many people, especially upper-management to adjust focus is a long, slow process. I'd guess it just took a lot of time to get coordinated.
They have an internal culture of "lets develop features for the companies that pay us, rather than the free-users". This got a lot of attention, because they started to realize that they can't keep heading in that direction and expect things to keep working.
Honestly git is distributed so I don't know why people wouldn't just setup another repo somewhere, say, GitLab and you could experiment with different workflows, etc and essentially have a remote back-up.