When the browser war was fought (and won):
- Netscape Navigator was actually a pretty terrible piece of software. I dare say they deserved to lose. Towards the end, most Mac users were running IE5 -- it was a better browser (http://en.wikipedia.org/wiki/Internet_Explorer_for_Mac).
- There was diminishing market interest in supporting alternatives to Windows because non-windows marketshare (Mac OS X, UNIX workstations) was plummeting. This allowed Microsoft embrace-and-extend to succeed.
- The web development field was nascent at best. Similar to how many web developers are moving into the mobile space today (and bringing their ideas of how to write apps with them), you had Windows-centric enterprises migrating towards writing web sites (not apps!) and bringing their ideas of how to do so with them.
I very much doubt that the web browser war would happen again in quite the same way. Between the availability of open-source browser stacks, the genuine viability of multiple platforms and vendors (iOS, Android, Mac OS X, Windows, and even Linux), and the established web development community (which would have to be co-opted), I don't think it would be quite so easy for someone like Google to 'win' a browser war and then stagnate indefinitely.