Yet another piece of Xamarin/Mono that falls down. No wonder Miguel de Icaza is now focused on Swift, Godot and Apple's ecosystem, all the promises done at Xamarin acquisition time are gone now. Mono Develop killed, after being renamed into VS4Mac, gone through a rewrite, only to be killed shortly after the rewrite reached 1.0. Xamarin.Forms rewriten into MAUI, with incompatible APIs. MSIL Linker had a better chance…
The license cost was high, and the MS acquisition came right around the time React Native and Flutter started to enter v1. I think they'd of been blown out of the water pretty quickly. At least Microsoft allowed Xamarin to get into enterprise .NET shops pretty quickly. There's a lot of B2B form based apps written in Xamarin. I worked on a pretty big one that made (and continues to make) a lot of money.
I've long assumed the point of the acquisition was because Xamarin did basically all the hard work of allowing .NET to be cross platform.