I literally saved two businesses as favors to friends. One by replacing a Mono app on Mac with Windows running in a VM. The second by doing the two hours of config work they were afraid of to host on Windows Server instead of a Linux box. (At the same damn price!)

Xamarin did an immense amount of work pushing that boulder up a hill. Glad you got results, but frankly it did a lot of damage to a lot of people. I say this as a Microsoft fanboy and someone who deployed sites you've heard of on Mono + Postgres + CentOS.

In the last year or two many .NET vendors went from "yes, it works on Mono!" to "it should work but no support." This indicates the formal death of the ecosystem to anyone but apologist hobbyists and thankfully we've gotten to a better place now.