I think even calling it a "design" is dubious. It's an attribute of these systems that arose out of the circumstance, nobody ever sat down and said it should be this way. Even Torvalds complaining about it doesn't mean it gets fixed, it's not analogous to Steve Jobs complaining about a thing because Torvalds is only in charge of one piece of the puzzle, and the whole image that emerges from all these different groups only loosely collaborating with each other isn't going to be anybody's ideal.

In other words, the Linux desktop as a whole is a Bazaar, not Cathedral.