While it does not right now and I doubt the team ever will do that, it is open source. I'm sure the team will accept meaningful contributions. A meaningful contribution here could be to make the flutter backend system pluggable enough that 3rd party backends can be used without modifying core. Then a web, desktop or any other backend can be implemented outside of it.

I know for a fast that the core team is open to the idea of creating desktop backends but does not have the resources to do it. They'll gladly accept any contributions towards that.