I don't think that is true. After all, they could make a gazillion bucks in licensing fees if they wanted to (in fact in the 90's they tried it).
The problem is.... apple has built their entire reputation on the marketing strategy... "it just works". Their computers work, right out of the box! (not meaning to sound like I am bashing other systems of course). apple works very hard at making sure that all the pieces are compatible with one another. Therefore, when they opened up their hardware and let other companies license it they found that they were quickly losing heir reputation for creating and maintaining systems that "just worked". Their motherboards, sound cards, video cards and everything else that come integrated into the system all work in harmony with one another far superior to when you give away that control.
Hmmm...I think what you wrote is probably fair. Still, Apple is a business, and you can't tell me that they don't know what they are doing by designing their computers in such a way that the consumer must deal with them for customization. I definitely buy the fact that they want to avoid conflicting hardware and software issues, but a smart PC builder can do the exact same thing, and it's more fun!

Also, I can build a PC with quality parts and have it work right the first time I plug it in at less cost than buying a Mac. That's a fact.
The down side to this strategy is cost. You can by a Windows based motherboard for a fraction of the cost of a Mac motherboard. It's a trade-off.
That's somewhat true. It depends on what kind of a motherboard you want and what you want your overall system to do. As I stated, I can build a quality PC cheaper than buying a quality Mac, however, I can also build a monster of a PC, but this will make the build a lot more expensive too. For example, I have two custom-built PC's in my house. One motherboard is of the quality type ($130.00 brand new) and the other is nearing monster type ($200.00 when I bought it brand new). I buy motherboards by manufacture, chip-set, and by layers. Layers signifies how feature rich and sophisticated the motherboard is. The higher the layer the better it is. At any rate, there is a lot more to motherboards than the average person knows.