Let me take you back to early September of 1998. We're in a federal court room, and Microsoft is busy trying to get U.S. District Judge Thomas Penfield to toss an antitrust lawsuit brought by the Department of Justice and a number of states. Remember, this was at a time when Netscape Communications existed separate from AOL and had its own popular browser. The DOJ argued that it was "technically feasible and practical" to separate IE from Windows 95 -- which, as you may remember, was a GUI integrated into a souped-up version of DOS -- and Microsoft insisted that it was impossible.
Mind you, Windows 95 originally shipped without IE. Clearly someone accidentally dropped some super glue into the code. If shadenfreude is your cup of tea, later in the multi-year trial there was even the highly amusing moment when Microsoft had entered into evidence videotape purporting to show that a version of Windows 98 (yes, it took that long) was sluggish if IE was removed. But it turned out that the videotape may have been of a machine running an unaltered Windows 98. So, was the problem then not removing Windows 98 from Windows 98?
Various experts would disagree as to whether the severing was possible or not. However, it's good to know that over the years, Microsoft must have further disengaged such key parts of the operating system so that, should another large governmental body demand a separation, that it would be able to comply. Or -- could it be that Microsoft might have been lying in the 90s? Oh, say it ain't so.