I'm bumping this because, though I disagree with certain key points you've made, I think even the bits I disagree with are well put compared to the all-too-typical, shooting-from-the-hip posts we sometimes see.
However, I think it's unfair to equate the term monopoly with any company like Apple that holds only less than 10% market share. If you don't know which company breaches anti-trust laws the most & tries to stifle competition, try googling for MS & anti-trust.
Also, ever wondered why HP, Dell or any one of a number of PC hardware makers don't design their own OS, rather than complaining about lost sales because of Vista's pre-SP1 shortcomings, as happened recently?
Apple's business plan may not be palatable to all, but how else do you think they can afford to constantly innovate, develop OS X, work on new products, etc.? Yes, their relatively high profit margins, some 30% as opposed to the average industry standard of about 10%, allowing them to hire some of the best engineering talent out there.
What you're suggesting would certainly guarantee that Macs would have to be sold at much lower prices &, yes, there would be short-term monetary gain for all consumers. However, long-term, we'd all lose out. How many years do you think it'd take before Apple's share price tumbled to record lows & inevitable cutbacks turned them into just another PC company producing mostly generic hardware?
What I would like to see Apple do to grow market share is either to go into very selective partnership with a quality PC maker to sell OS X computers that won't cannibalize Apple's existing range, for eg., mid-towers (not comparable to serious workstations like Mac Pro), or simply striking a better balance in a downhill economy between profit margins & steady growth. I grant the former is highly unlikely. If Mac sales continue to dip however, which recently they've done significantly so, I think (at least I hope) we may see slightly cheaper Macs in the coming months.