[ChuckMcM]

It is true, Sun did it poorly :-) What Apple has that Sun didn't are vertical product stacks. A 'Macintosh' company has its own hardware, software, and (shared) sales channels. The 'iDevice' company has its own hardware, software, and (shared) sales channels. I think that separation could work.

From where I could watch, Sun's biggest issue was that they forgot they were a systems company and started trying to be a components company. They had also pretty much become completely afraid of 'open' systems at that point. Playing tricks on competing SPARC computer companies, screwing up the OS portability, etc.

[microtherion]

As far as I can tell, Microsoft suffered similar problems, with their desktop oriented divisions occasionally holding back the mobile divisions. It's not like Apple never suffers from any organizational dysfunction, but I feel that separating divisions actively incentivizes dysfunction.

macOS and iOS share quite a bit of software, both in the sense of code bases that have overlap on the two platforms, and code bases that need to work together (e.g. for handoff, or features like Apple Watch unlocking a Mac). Not so sure about the hardware situation, but there is at least some sharing going on. And in many cases, the people behind the technology are shared as well.