Your mileage may vary but my opinion: Because its controlled by Microsoft. ASP.NET Core brings everything necessary to develop a web application, from an ORM, t

Your mileage may vary but my opinion: Because its controlled by Microsoft. ASP.NET Core brings everything necessary to develop a web application, from an ORM, to a web server, to a router, to an HTML templating language, to a client-side SPA framework. All components are designed to work together and have high quality documentation. That makes it easier to get started than say Python where you have to depend on multiple third party libraries with different support cycles, API styles, or even async programming models (e.g. gevent vs async/await in Python). And you can still swap components out if needed. Not saying Rust or Python etc. are bad for writing startup software. Given the ecosystems I personally find it faster to get started with .NET because of the reasons above.