Consider other historical antitrust battles. It's often not about dominance in one niche, but leveraging that dominance into other areas and limiting innovation there.

By your assertion, you would be happy to have had IE tightly integrated into Windows since the early 00s and make it extremely difficult for typical users to install another browser. Competing browsers would also be at a technical disadvantage to IE since they don't control the underlying OS. After all, Windows is popular, why shouldn't they...