That's because those weren't completed in time due to feature creep and second system effects (Apple's Pink/Copland), lack of interest and slow progress (Hurd), etc. Midori is just a research project, so noone pushed for it to be adopted anyway.

With a completed OS (which nowadays isn't so difficult, large parts of the stack are either ready or there for the taking), and a big vendor behind it, it's another story. Microsoft pulled it off with NT, and Apple's OS X was a whole new OS as far as Mac customers were concerned (the fact that it already existed as NeXT didn't matter much -- it still required all new software (it didn't run old NeXT stuff as is), new drivers, had a new SDK that Mac developers had to cater too, etc.

Besides Android is not like a full desktop OS Linux -- it abstracts most things for apps through its SDK/"Java", and Linux is just the kernel.