NewHype valuations reflect how confident current investors are that later investors are still coming and have nothing to do with specific profit models. Maybe the hype will pay off or maybe it won't, but during this phase all I need to believe is that I can get out before the tide turns.
At this point, the carrot that keeps investors coming is that many many people still believe at least one of these companies will become the next IBM/Microsoft/Apple/Google in one way or another and we don't know which one yet.
It's just buying tradable bets on a horse race that won't see its end for several more years. One horse could win, all the horses could drop dead, and none of it matters today: the game is in deftly trading those betting tickets as the odds shift.