Yeah, a lot of the .NET stuff is low-paid, low-challenge big business work (and the only high-visibility "cool" .NET work is at MS).

There's a few positions that intermittently pop-up doing "cool" work in .NET: usually startups, or small teams; the chances are much rarer, and you have to be in the right place at the right time -- but your chances are much greater than someone who's coming in from any other ecosystem (e.g. Javascript back-end).

Or in other words, sniper vs shotgun approach. You're going to get less targets overall if you specialize; but it'll be much easier to have a strong chance of being "the best" in the crop of applicants (or even for marketing purposes, a la personal consultancy).