There is so much software out there written in WYSIWYG VB .NET and C#/.NET WinForms/WebForms editors. Granted most people aren't writing new stuff in them, but for a while they were quite big in the .NET world.
On the native desktop side yes (btw qt is underrated) it's very mature, and I think people were just too busy with building stuff for the web (at least from a non .NET developer).
What's even crazier is that you could have a web application in your browser built by some monolithic UI builder tool and wrap it around a thin client and ship it with a six digit price tag for enterprise, they won't know the difference.
If there was a way to generate a react.js app using Visual Studios or maybe even a dumbed down version suited for building front-end web apps, that could be ideal but would it be in their best interest to help their rivals? I know the whole going open source is a new thing for MS but they won't own 'React' and be able to monopolize the new era of 'I taught my grandma how to build Hootsuite with just click & drag'. Unless they create their own front end framework and own the platform that is the web which is constantly being voted on from the capricious developers and new adopters.
There is so much software out there written in WYSIWYG VB .NET and C#/.NET WinForms/WebForms editors. Granted most people aren't writing new stuff in them, but for a while they were quite big in the .NET world.