Having more than one job doesn't mean I'm necessarily self employed. I could work at a supermarket during the mornings, and a cornershop in the evenings, and still be an employee in both cases.
In the case of a driver, they get the ability to dynamically pick their rides in real time, and choose from the different apps the one that pays the most.
There's a paradox in this: Uber and its competitors would ideally like their drivers to be 100% committed; yet they also need the drivers to be able to work for several apps as a defense against requalification as an employee.
No, they simply don't allow drivers to work for competitors with a simple trick: designated routes. Working within the same day on different apps is not enough, it has to be different apps => multiple clients => one trip.
If an Uber driver were to pickup a Lyft user on a trip and to drop them off away from the main algorithmicly imposed road. Uber would warn the driver within a few days, regardless of client reviews.
I was not clear enough: indeed, they can't drive simultaneously different clients (from different apps). Instead, while they are waiting for a new client, they have several apps open, and if they get ride propositions from different apps, they pick the most lucrative one.
I don’t see why the same couldn’t apply to supermarket employees, where you can dynamically choose your shifts in real time and pick the highest of all the available work.
I mean there are even a number of worker supply firms out there that provide workers on this basis. A business needs people to clean floors, they issue a request to their supplier and they supply the nearest, cheapest available workers.
I'd say the only way to "simultaneously" work for both is to have a rider from more than one service in the car at the same time. Probably 0% chance they'd have an overlapping route, so you'd have to go off-route for one of them, and I'm sure that wouldn't go well. But for all the drivers I've seen that use more than one service to find riders, never seen this happen.
Just curious, when are you "working" for uber or lyft? I'm honestly not sure how it works. Do you collect an hourly wage when you are waiting? Or do you only collect money when you actively driving a passenger?