Lots of things.
They decided not to build a MIDI "break-out" box a couple of years ago, even though the product was ready for production according to some sources.
They decided to stop making printers.
They decided to simplify thier product lineup, to have two (then three, then four) lines to sell. Desktops, laptops, (and eventually) mobile phones and tablets.
They decided to stop licensing their OS to third-party hardware manufacturers.
They decided to not go open-source.
They decided to no longer sell previously successful products when they felt they had reached end of life (iPod Mini) and when they didn't align with the rest of their products (white MacBook).
They decided to not sell computers based on specifications, but instead on the experiences that such devices provide, allow, and support.
They decided to not have a physical keypad on their phone.
And so on.