People who knew what they were doing with computers used Netscape until it died, those people went to Mozilla suite and then Firefox (well, Phoenix then Firebird then Firefox). But that was a shrinking minority of people on the internet at the turn of the millennium.

Practically everyone else used IE (90%+ of web traffic at its peak) and continued to do so until Google released Chrome and shone a light on how little Microsoft had been doing for nearly a decade.

Dominance was dominance however they got it, and they pissed it away through complacency, somewhat similarly to what they're doing now.

This is your rose tinted hindsight fantasy.