ADB ports only finally went away when USB came out. But I do have to give Apple credit, because those fruity-colored iMacs with the hockey puck mouse, that had only USB ports... those are really what got USB to become fully adopted. PCs had USB ports for a while before those came out, but nobody made any peripherals, probably because Windows had really crappy support for it... Once those fruity iMacs were released, then came the flood of USB stuff.