Meal delivery could be big for them, however, it's easier to have competition there. Their value is name recognition, which is more important traveling (ride sharing) than in any single local market (delivery)
when you remove the cost of paying a driver, cut fuel costs to 3 cents/mile, and eliminate the obligation to tip, self driving EVs will be so much cheaper that uber won't be able to compete. And it doesn't matter if many people use them at first, what matters is when the safety data comes out and proves they are vastly safer. I don't think there is anyone who has used many uber/lyft/taxis who hasn't been in cars with drivers who scare them.