Awwww come on, did you miss some of the recent legal case.
Lets not confuse 'perfectly happy' with 'ignorance is bliss'.
Most Windows users are ignorant of the fact that their are better alternatives, and MS used questionable tactics to make sure it stayed that way.
Microsoft knew that many Windows users are not savvy enough to change their browser from the default. They used strongarm tactics to make sure that PCs were not being sold with alternative browsers present.
If joe public were sold PCs with alternative browsers installed (as used to be the case) then many would choose to dump IE.
I installed Mozilla on my girlfriend's PC. Neither her, nor her 8 year old daughter, wish to change back - and they are non-techy users.
Quote from 8 year old "its quicker and nicer"
Couldn't have put it better myself.