Microsoft overreached by giving away IE to killing Mozilla. That's what really caused the consent decree to get issued. I find it hard to believe that you would have gotten Amazon/Google/Facebook if Microsoft had a stranglehold on the desktop.
I don't agree with your take on Amazon. We can't trust the US government to police the large companies. The large companies are too good at (a) walking right up to the line or (b) buying off the people who make/enforce the laws.
Don't understand the downvotes either.