[makeitdouble]

On the "why", I'd look at it the other way round: there was absolutely no downside for MS for a very long time. Any money they'd "lose" on browser sales were largely compensated on OS sales (even as they also were pushing basically free OS distribution by letting piracy run rampant, also giving them an insane OS share).

With no penalizing cost and no consequences (the DOJ had a first anti-trust probe that led to nothing. If the US did nothing they assumed no one else could stop them), there's just no reason to not shoot for the moon and go for total market domination.

It's only after hitting the EU antitrust case and the later US cases that they changed course and factored the new costs in their strategy.