Fair, but I would describe them more as well-engineered skyscrapers. Or even simply good city planning. They're large structures designed around the idea of flexibility and growth from the outside. Ironically, both of these described platforms have orders of magnitude more functionality in their 'bazaar' app-stores than the foundation itself. The foundation enables the market to work, but in itself it is simply a very well-designed support system.
I guess you're saying that there's no reason UNIX should be different—that it has somehow become a disorganized mess of libraries and code re-use, and that it is broken.
I don't see this. Android and iOS are like brand new cities; Dubai and Abu Dhabi. UNIX is Paris. Perhaps you can make some updates to the city infrastructure, but in the end the streets are still cobblestone underneath, designed for horse carts and not cars. But you have the Notre Dame at the center (ironically, a cathedral), the architecture, tons of history, you have a thriving culture and countless people working and playing in this city every single day with great success. You can complain about it all you want, but there is a reason that people are fundamentally attracted to it.
I think you're right about a lot of things, but if you propose rebuilding Paris, well, you may have some opposition. I think you might want to build a new city, rather than trying to build over very old history with some ideal of the cathedral you think it should have been. And to use your examples again, that strategy has been very successful for Android and iOS.