Some of us remember times before Opera, Galeon et al. (and I am one of those people who actually paid for Internet Explorer when it only shipped with the Windows 95 Plus Pack).
I remember the day IE introduced Javascript (v.3 I think it was) & going round chatrooms that let you post HTML and griefing with inline images.
IE was very forgiving with its HTML engine. There was a time when missing a /td or /tr would leave you with a blank page in Netscape but IE rendered the page just fine. This led to hundreds of websites that only rendered in IE because that's what people checked them with.
So in this way it was the "best" browser because you needed it to browse half of the web!
IE 4 was far and away the best browser in its day. Nothing else was as fast and as reliable. Netscape had devolved into a steaming pile of garbage which had horrible resource usage problems aside from being massively unstable. Other competing browsers weren't much better than netscape either. It wasn't until years later that things changed.
But Netscape ran cross-platform, without which the WWW would have devolved into a Windows-only niche product. And that would have meant the only tablets today would be running Windows.
I don't think that follows. Also, it's not as though Netscape didn't have it's moments either. There was a time where it was better, a time where IE was better, a time where firefox was better, a time where chrome was better, and so on. Time marches on.
The original idea came from ActiveX, but it didn't take off until it was implemented across browsers via JavaScript as XMLHttpRequest over the next 6 years, and didn't become "Ajax" until the Adaptive Path blog post about Google's innovations with Maps and Gmail in 2005. Microsoft then added support for XMLHttpRequest a year and a half later in late 2006 with IE7, which of course had very little adoption, particular among businesses, because of IE6 (see IE6 @ 49.8% and IE7 @ 17.1% IE market share at beginning, March 2007, of this graph: http://www.w3counter.com/trends).
IE4 was the first browser with dynamic HTML (DHTML).
Microsoft evangelized the combination of DHTML, Javascript and ActiveX data controls to build applications similar to what we now call AJAX. Microsoft was ignored for various reasons.
Microsoft introduced XMLHttpRequest and evangelized DHTML, Javascript and XMLHttpRequest. They were ignored again.
It was not until the introduction of Gmail and Adaptive Path's coining of the term AJAX that people finally got it. By this time, Microsoft had already put IE on the back burner.
Eventually Mozilla / Phoenix / Firefox picked up the mantel. Then (somewhat) Chrome, though it's getting really effing annoying these days.