But why? ASP.NET Core is one of the best web frameworks, extremely modular and flexible. It's low level components (http server, routing) can be used as a foundation for new web frameworks.
I don't think so.
The fact is there are very few dotnet web servers. ASP.NET Core is supported by the owner of the dotnet langage who is also the M of the GAFAM.
There is some place in the ecosystem for other alternatives