For me, it was Firebug not some noble agenda. Microsoft actually had some quite good debugging tools, but getting the tool chain setup was damn near impossible.
I've been doing .NET dev for the last decade. I have no idea how to get the whole browser part of the toolchain working with Visual Studio. I just don't bother. The client side debugging is done with a browser that is basically Chrome (Brave these days). You can set up everything to go through VS but there I don't see any benefit in doing so.