1. The innovation was less the app and more solving supply problems. No app will be able to change that for the taxi business.
2. Competitive advantage in this space is having more drivers and less wait time. That drives folks to use one provider over another. The lock in isn't the tech, but the availability of rides.
You're right that the lock in or network effect in the ride sharing space is very different than other big tech cos (FB, Netflix, AMZN etc) in that they're localized, and should result in more competition.
The bet investors are making is that the market will shake out with one category leader, a runner up and virtually no competition beyond that. Should be interesting to watch.