You may have a point with regards to Webkit, however even that is potentially tenuous. The difference that you are missing, and that was addressed is how Microsoft levereged their market postion in the OS market (>85% in the late 1990's) to stop vendors and OEM pre-packaging an alternative browser; USA vs Microsoft was never about IE being bundled - that came later and that was the EU - it was always about how they killed the main competitor to their browser with threats.

* Edited for spelling