.NET has already taken the world by storm if you consider actual usage. It powers software for the Fortune 500 and millions of small businesses. It lets you build desktop apps, websites, frontend SPAs (Blazor), mobile apps (Xamarin), backend services, and games (Unity).

There's no need to rewrite working .NET Framework apps, but .NET Core has seen massive uptake with cross-platform development and runtime, incredible performance, and interoperability with just about every other common open source languages and projects.