I don't know what Apple could bring to the TV market either. If I did, I would do it myself, and be a lot richer than I am. However, I do know that they can do something.
I have loads of different boxes attached to my TV, to receive signals from various sources such as DVB-T2, DVB-S2, Ethernet for steaming and on-demand TV, USB, Blue Ray and so on. Each has its own remote control, and different user interface.
Live TV should work the same whether it comes from IPTV, aerial, satellite or cable. And the UI for on-demand should be the same no matter where it is coming from. It also needs to be much easier to use.