If IE was to be web-standards compliant perhaps then the dominance issue would be a moot point... but IE tends to redefine web standards and there are soooo many work-arounds and fixes to get it working and perhaps with an IE browser on every Windows desktop herein the danger lay... the web becoming IE dependent. Opera, Firefox etc needed (and still needs) fixes for certain websites BECAUSE these are IE compliant... the web devs just made sure they worked with Microsoft's browser and accompanied proprietary dependencies and left it at that... all other browser development would thus also need to rely on Microsoft IE foundations UNLESS the shift to "browser agnosticism" according to web compliant standards can be actively promoted.
Hence this movement to un-bundle IE from the OS perhaps ?? Also thus the push from Microsoft to redefine these standards.
At some point perhaps a line was needed to be drawn in the sand... self regulation only works on a level playing field.
Windows N is proof that Media Player and IE need NOT be baked into the OS... and that it can be fully functional sans the obligatory install.
A part of me somehow wishes that Microsoft had just bought Netscape / Opera and baked this into their OS, pulling it into WWW standard compliance... Internet Explorer, pfffft, the less said about it perhaps the better.
Sooooooo.... waffle waffle wall of text... the dominance threat was not IE itself, but the reliance on it of Windows users as the "out of the box" browser that forced the entire internet to adapt to IE's butchering of WWW compliance that was the stifler of innovation and competition... and this needed to change, thus the browser choice ruling methinks.