Makes perfect sense if you know your history: _soft_ware for _micro_computers, because in the era where Microsoft was founded, the word "computer" was associated with room or building sized mainframes. Minicomputers were the size of a rack or two and microcomputers / home computers were ones that fit on top of a desk.

Microsoft DOES make sense though - tiny software...

I dont know if gibson took it or coined it in neuromancer but it at least makes sense as a name for a thing. This isn't the same as "random noun" for a company name.

At least their old name made sense, "micro-soft" - software for microcomputers.

Tbf Windows has windows in it

It's not called Microsoft Ads 2020