Comment A few thoughts on why this might have failed .... (Score 1, Offtopic) 190
I know someone, above, said "Hey idiot... it's about the lack of drivers!" I'm not going to even attempt to speak to that, because I don't know enough details to know if Sidecar's business model would attract "enough drivers" or not?
Off-hand though, I do know I've taken shuttle buses before where the driver only accepted cash and charged around $8 to drive me to an airport from a hotel, and he didn't have more than 1 or 2 other passengers when I got on the bus. So that tells me that yes, some people will gladly drive you around for lower rates than are charged by a typical taxi service or Uber.
I think one of the big obstacles to a Sidecar type business might simply be the fact that you're expected to essentially "make an offer" for what you'll pay. If you advertised a fixed rate that was clearly almost 50% lower than the competition -- it would probably do a booming business (provided it was advertised sufficiently, etc.).
I know where I used to live, several restaurants experimented with a "pay whatever you like" program for food, and truthfully? A large percentage of people who'd otherwise eat there avoided it while they did that. I think that's because, by and large, Americans are adverse to haggling/negotiating on prices. Sure, we have a culture that expects it'll happen on BIG purchases like a car or a house -- but for the "every day" stuff, not so much. (Even with cars, people are flocking to the "no haggle/no pressure" pricing models.) Even with something as simple as hiring a babysitter for a couple hours, people are always hesitant when the sitter says, "Just pay me whatever you think it's worth." Will you offer too little and offend the person, or cause them to prefer not to work with you in the future? Will you pay more than most people, essentially ripping yourself off?
Now add the fact that with a need for a ride someplace, you're probably in a compromised position. This isn't like going out to dinner where ultimately, you can just take it or leave it. You probably have a real NEED to get someplace by a certain time deadline. The last thing you want is to be late, simply because you didn't offer enough money vs. the next guy for a ride and got ignored.