I think they’re very happy to have the 2 parallel product lines; they might overlap a bit but who cares, business is about the numbers, not ideological purity of product lines.

The line they’ll probably never cross is that the Mac can run software in a (mostly) non sandboxed mode, with unrestricted background processes, which means it’ll always be the platform of choice for developers. Those extra restrictions on the iPad makes them more free to push it/experiment with it in the direction they wish (for better or worse, as we’ve seen with all the wonky windowing implementations, although the current one is mostly fine)

I love my iPad for drawing/photography, reading comics, and its extreme portability; I love my MacBook as a developer and as my main productivity machine.