Firstly - Even if phones become as powerful as desktops, games, creation & editing of text documents, graphics work, ETC., ALL benefit from at least a reasonably sized screen.
Secondly - If portable devices such as phones, tablets, ETC. Ever become equal to desktops, They’ll still need a backup solution in case of hardware failure & most especially, THEFT of the portable device.
Thirdly - There’s uses for BOTH Desktops & portable devices. Each has it’s own niche to fill.
It’s good the brain frazzled Ozzie was fired because he’s out of touch with reality.