You left out "C) Tech giants emphatically encouraging everyone to use only and solely their smartphones". We all know the reasons for this (collect and sell personal data, and keep people watching ads by offering click and rage bait), but the tech giants increasingly have incentives to keep people from writing code, or performing actions not in the tech giants' best interests. We, as a society, are not going to be producing anything en mass except smart phones. Very large mass markets are the only reason computer hardware was cheap.