In this scenario, dispatch would basically be a public utility, and drivers could trust the algorithm not to cheat. I.e. since Uber B and its competitors would be running any driver incentives, Uber A wouldn't even know about it. (And legally shall not know such things.)
I realize this is a half-baked pipe dream, but an interesting thought experiment.
But since Uber B has the brand recognition (through its UI), the question is if there will be a competitor. Nowadays, it seems that consumers converge more and more on a single brand for any service/product, which is probably due to the internet/social media.
This only seems true (at least over medium to longer times) for certain classes of product/service, namely those where network effects actually provide real value to consumers. Many products have tried to artificially integrate features that would initiate network affects (for example niche social networks for fitness trackers) but they end up making the product less usable because they're not part of the core value proposition consumers are looking for with that product.
so many stories of not getting any rides when they get close to a promotional number of rides. You can't prove it but they are very suspicious that Uber does it
Poor Abi...
Moreover, they have much more opportunity to do it since a strip club and barber salon have a lot fewer rented spots (ones/tens vs hundreds/thousands) and there is more ways Uber can be sneaky about it. (Oops sorry it took us 10 minutes to find you a passenger)
OH there's also the fact that Uber has the ability to arbitrage. Since the drivers who payed in are more costly to Uber to send passengers to than the drivers who didn't. Unlike the other industries you mentioned where presumably everyone has to pay in.
Kalanick and the bros did a hell of a job trashing the company reputation.
https://www.theverge.com/2017/9/8/16273378/uber-fbi-investig...
There's also a pretty obvious mechanism for selection bias here regarding which type of situation we're going to hear about. Few people are going to write up a post saying "I got close to my bonus, and then I got more rides, and I got my bonus, and it was fine", whereas people who feel like they're getting screwed tend to be very vocal. So the existence of these stories tells us next to nothing.
This offer exploits loss aversion on the part of those drivers (once they take it up, they don't want to "lose" and have it not be worth it, so they might end up driving even if fares are low).