I bought into Sooloos because it was a complete, integrated, end-to-end packaged solution
Absolutely right. And there will still be a significant number of current and future users exactly like that. That's why Sooloos will still be a very viable product for some time to come.
The comments thus far today just emphasise what a good situation for users this is.
Some users will stay with Sooloos server; some will use Roon.
All users here should have the good sense to use Meridian endpoints so that is a good thing for M.