If there are competitors (e.g., Waymo) that have self-driving that's significantly cheaper, then Uber and Lyft can't compete. So it's a huge potential threat to their businesses. And if self-driving makes rides much cheaper, that can significantly boost the size of the market. But that does not imply that they can't be successful and profitable businesses in a world without self-driving cars, which is the frequently-made claim in the top post.

Can't speak for Lyft leadership, but I think Travis and Dara have very different perspectives on self driving.

As for the existential threat narrative, consider that there are many places that sell cheaper/better food than McDonalds, and yet, McD is everywhere. I don't think technical merit alone is going to win the rideshare pie.

Well, if they were only afraid of them, rather than needing them, they're in decent shape, 'cause the last few years have kind of given the impression that self-driving cars aren't coming any time soon. They've been "90% here" for at least ten years but that's not enough.