Since Webcore now also runs on Hubitat, I believe some of their most active developers are now using that platform. So not relying on ST at all. Beyond that, you’re right: they aren’t collectively going to provide an alternative hosting solution, so I don’t see a lot being done. For those who want more details, there’s a discussion in their forum, which I know you already participated in.
Also the original primary author was hired by SmartThings a couple of years ago to work on the Rules API and other official features, which probably explains the timeline break in rapid Webcore development.