I can see how OP would come up with this - Angular w/Typescript is probably the "Microsoft Way" choice for front-end JS and has good support in VS.

Once you've been exposed to a bit of that it would be natural to get curious about other parts of the JS ecosystem i.e. node.

Most C# developers who followed this path probably worked on enterprise-level custom software which is now web-based or they worked on ASP.NET applications which have been replaced by TS/JS web applications.

One example would be SharePoint, which has shifted fundamentally from full trust farm solutions over to client side SPFx solutions running through APIs due to Office 365.

Another example would be UWP, which has pretty robust JavaScript support, meaning someone could switch from C#/XAML over to a JS app that more closely matches the web front ends of their site.

And really Angular is a pretty simple leap for anyone familiar with ASP.NET MVC.

In what way does UWP have JavaScript support?

Interesting. After the Html5/JS disaster a few years ago I would be reluctant to bet on this. Also makes me wonder why no TypeScript.

No TypeScript? Anywhere there is JS there is also TS, since it compiles to JS.

The first major version of TypeScript was basically "C# in JS clothing". It made the migration from C# SUPER easy for many that were used to the C# way of doing things.

Then throw in that many C# devs already had to know some JS for doing web applications in .Net, and you have both the motivation and the stepping stones in place to make it an easy transition.