Writing Win32 programs in assembly was a niche in the late-90s. This post inspired me to do some googling for a project I was familiar with back then and discovered the author has brought it back to life at https://github.com/ThomasJaeger/VisualMASM.
Regarding UNIX, due to macro assembler nature of K&R C, and the spread of UNIX source tapes, there was never an Assembly culture like on the home computers where we had an integrated experience, of hardware and OS, that defined the platform.
It is similar to how John Carmack describes the IDE culture from those of us that grew up with those platforms, versus UNIX.
MASM SDK itself use various tools from VS (including the assembler "ml.exe").
What makes is more useful are various macros/functions bundled in MASM32lib which makes programming Windows in assembly easier (this lib are still regularely updated).
If you don't like MS assembler, the good thing is you can use open source ML-compatible assemblers like:
> Nowadays I mostly work on Linux and Mac, and wonder why there's no equivalent project exist. Perhaps those Unix coders are satisfied enough with C...
I think a lot of the win32asm scene overlapped with defeating copy protection and making mods/cheats for games, not really Linux and Mac territory (at the time at least)