IIRC the problem was way beyond that and was actually to do with how IE4 had desktop integration - in Win95,Win95 OSR2 and Win98 - that netscape, etc couldn't compete with.Even back then, I think MS had the option of setting the default programs. The issue was that they stepped in and blocked OEMs from preloading the competition which was basically the definition of monopolism.
The integration relied on Windows API features that were never fully published for external developers IIRC, and even when preview APIs were fully documented, Microsoft changed the release API without communicating this, so developers like Novell (word perfect) couldn't compete at a fair level with Office at release, because their program couldn't be ready as they'd developed on API calls that didn't finish up in the product - which is fair on one count - as Windows versions needed to release to be finalised - but could certainly be used as a method to unfairly kill off competition IMHO.
At the time when the problem first occurred browsers were still distributed physically by CD as a free ISP service signup disc(or downloaded from ftp client, which basic browser document retrieval is essentially built on). With MSN launching in competition to AOL, Yahoo, etc, the integrated IE browser and with prelinked favourites to MSN/hotmail certainly gave competitors reason for concern, and certainly looked to me like it was more like a AT&T/Cable&Wireless problem again if left unchecked.