They couldn't make Blizzard any worse.
I don't use or have any interest in gaming subscriptions but have no issue with them as long as they don't affect non-subscriptions.
Unsure if gamepass games use UWP or not or a combination of UWP and Win32. I know some games have been cracked and I want to say those UWP games are tied to at least a minimum of whatever build of Windows they were released on (possibly untrue but I don't care for UWP games so don't have any), if someone wanted to they could probably subscribe and crack the game and then end the subscription but likely only legal owners who care would go to that length. Most legal and non-legal would just download the torrent of an older version of the game since AFAIK the UWP vers don't get much attention.
Hopefully the NetFlix of gaming (streaming) by the idiots subscribing to it will fund the non-streaming but more than likely the devs will give up supporting the compatibility issues of supporting non-streaming. Why spent most of your time developing for issues of a bunch of different hardware and offline situations when you have could just code content for your game? Also you can't monitor what you can't see. That'll likely be what does it for the most part. There will always be a niche though but hopefully the games you like will be in that niche, if not backlog it is. Currently non-streaming far outnumbers streaming in gaming so we have that going for us.