I do think they actually invest significantly into laptop/desktop development. If you look at the teardowns at iFixit, they are pieces engineering art. No other manufacturer offers that nicely designed devices. Just think of the new Mac Pro having no internal cabeling, everything, including the extra power supply for the graphics cards, is on the motherboard.

But of course, one can (and I do) disagree with some of their design choices, like non-exchangeable SSD and using far too much glue in the designs.