The Uber app was the original innovation, but it's not particularly innovative anymore. Besides Lyft, traditional taxi companies have similar apps in some markets.
Skirting regulation and good labor practices were also supposed to help, but that can't last once you become competitive with the establishment.
Self-driving cars were supposed to lower labor costs, but that's not going to be a thing for decades if it ever works. But even if it does, it won't be an exclusive technology. They won't be able to make any more profit from it. If their costs go down, so will everyone else's and they won't be able to undercut the competition without continuing to lose money.