That's why you should never start the Uber of X and the Amazon of Y. Because if the actual Uber and Amazon see that the market is good they will massacre you unless you're fortunate to get an offer from them.
Fwiw Instacart had the same problem, and it succeeded, even after Amazon acquired Whole Foods. It's really case-by-case, and depends on so many factors.
Instacart is doing well but I think it's still too soon to call it a success. Hell I don't even know if I'd call Uber/Lyft a success yet.