Third-party stuff isn't sufficiently sticky. If Apple wants games on their platform, they need their own controller. It might even be best if it comes in the box.
I don't, however, think they really care that much.
The thought that they don't care that much is really strange, because every single keynote that I can remember has included game demos. They always use game demos, from AAA game developers like Epic, to come out and show off the latest capabilities. They could take a sizeable chunk of PS4 and Xbox One customers very easily - fund the development of some genuinely AAA, exclusive games, bundle the controller in the box and the thing would sell like hotcakes. Nintendo is somewhat safe because their IP is much more valuable than Xbox or Sony, who basically offer the same games with a few notable exceptions.
Even the WiiU Pro controller had clickable sticks.
Even the switch joycons, which I think are incredibly impressive with how much tech is crammed into them, are pretty awful to actually control with. The only reason I think they get a break is because they are designed for portability.