I personally think that we're not yet going out of the smart phone era . That there will be a new generation of " Smarter " phones : Transparent , lighter , slimmer and they will be powered by AI through our Home PCs and connected to the cloud , their content will be beamed through certain surfaces and even hologrammed . To keep hands free from all of that an Ear piece with a mic will suffice as its accessory wearable device .