That issues list is misleading since the mt76 covers a multitude of devices, all of which report issues to the same place.
Support for a device will go for a long as there is someone who wants to maintain it. Even the 4/32 devices could be maintained to receive security updates backported to a version of OpenWrt they can run - but only if someone wants to invest the time and effor to do so. And if it happens, it'll be someone like you @BenSisko who does it for their own device because no one else has, and if someone else happens to get use of it, well, that's ok too..
I just added OpenWrt support for a device that was 1 of less than 500 and the ODM went under in 2015 :D. Doesn't mean it can't be supported.