The replacements they had in Austin never filled those shoes unfortunately. During SXSW traffic spiked and all the replacements were crashing and people were getting "stranded" with no rides.
Sure, but since then things have kept improving. From a technology point of view it's only going to get easier and easier to run a ride-sharing service.
Is that why several of the Austin replacements have now folded since Uber/Lyft have been back for a while?
No, it's not.
I've had Uber crash during traffic spikes, and was "stranded" for a few hours while I waiting for demand to calm down.
Have you tried using Uber or Lyft during any large event? They are just as much of a clusterfuck. Either the app crashes due to so many phones nearby clogging the network, or drivers drop the ball, either cancelling on you or accepting your ride from 30 minutes out, trapping you for fear of getting a bad rider rating for too many cancelled rides. Getting into the wrong rideshare is also surprisingly common and concerning, especially when these large events involve a lot of drinking. I usually resort to walking a mile, maybe more, from the event before I attempt to call up a rideshare.
I use Uber and Lyft all the time during Re:invent which is, by any reasonable measure, a large event. It works great and works even better than Amazon's buses (which themselves are pretty good) if you need to cram a lot of transit into your workday.