For instance, fast-forward a few years. Let's say Apple has become the dominant PC manufacturer (crossing 50%) and OS X has overtaken Windows in terms of new sales. Might the anti-trust police come into town and force Apple to start licensing again? No. Microsoft got in trouble, because their business model is based on licensing. They can't (or at least shouldn't) be able to treat their OEM customers unfairly, or strong-arm them.
Apple avoids this issue, because it only sells the OS for its own products. It does not control the fate of other companies. For example, let's take Nikon. They make lenses for their Nikon cameras. They are not obligated to make lenses for Canon or Leica cameras, even if Nikon had 100% of the market.
Remember that's why IBM back in 1980 was reluctant to design a proprietary OS.That seems like an odd statement. Got any source for that? Either it's not true, or IBM were being incredibly stupid, because making their own proprietary OS would have protected them.
No, anti-trust rules also prohibit bundling. You can't use a dominant/monopoly position in one product or service to try to create an anti-competitive market in another product or service. That's partly why the EU forced Microsoft to sell a version of Windows without Media Player, and why even in the US some makers of competing media players sued Microsoft to force them to include their products in addition to Windows Media (they argued that Window's dominant position threatened to make Windows Media the dominant music format).
IBM had settled a previous anti-trust case involving mainframes (where they sold both hardware and software) and were afraid of running afoul of anti-trust matters by having a proprietary IBM OS bundled with the hardware.
Apple is in both the hardware and software businesses. If OS X becomes the dominant operating system (i.e. having the largest market share and being the OS that most commercially available software runs upon), it runs the risk of being deemed by anti-trust authorities as being in a market-dominating position. There's nothing wrong with having a monopoly or dominating position. However, what constitutes "abusive practices" changes if you have a monopoly. Microsoft had no problems tying MS-DOS Compaq and others back in the 1980s to their OS contracts when the "IBM" platform was fledgling and there were plenty of OS choices. Once Windows got to such a dominant position, things changed. They should have changed their contracts, but didn't.
If (and it's a big if) Apple were to gain a majority share of either the PC or OS market, then its practice of bundling the OS with the hardware could become a problem. In that (hypothetical) scenario, Apple could be accused of using its dominant OS position to force users to buy its own hardware when there are lots of other hardware products that (in theory) could be compatible with its OS. One possible solution, if it comes to pass, would be to open the clone market again. That won't help Psystar, since Apple is nowhere near that situation right now.
