why on earth are the 2 largest and highest valued technological companies in human history repurposing mainframe multi-user computer operating systems from the

why on earth are the 2 largest and highest valued technological companies in human history repurposing mainframe multi-user computer operating systems from the 1970's (extended even further with sandboxed app containers!) for mobile phones!? It smacks of deliberate incompetence to sell hardware. iOT on top of this just smacks, again, of deliberate incompetence, to either sell hardware or raise the attack vector profile (the NSA loves you!) why on earth is there still no reasonable competition to either android or ios?