I know the cab and limo business pretty well (check my /. user name), and I give Uber and Lyft another two years before they start fading. Drivers will get tired of paying high commissions, having all their income reported to the IRS, and beating up their cars like crazy. I survived and did well in the limo biz largely because I could do most of my own repairs and knew low-cost shops that could handle the rest. If I wanted to go back to driving for money (no need - between SS and the "side" freelance work I do, I'm fine) I'd probably work work with Uber until I built up my own "book" of business, that is, personal customers. Then I'd say "sayonara" to Uber, just as I did to the cab company as soon as I had enough personal business to tell them to go screw themselves and a threatened RICO suit against the Baltimore cab companies and the MD Public Service Commission opened the business to anyone with an inspected car, good commercial insurance, and a clean criminal record.
My little group of owner/drivers competed successfully with Boston Coach, Carey, and other national companies. I have no doubt that I could compete successfully with Uber, too. Lyft? A low-rent gypsy cab service. I could beat them, too, but why bother? I did a little gypsy cab work many years ago, but didn't love it.