This is a network game, so market share is everything.
Market share means drivers stay busy and make money. Market share means riders don't have to wait a long time.
Uber gave massive discounts for a long time to establish their market share, and it suited their long-term vision just fine.
Same strategy seems to be working well for Lyft, too.
[1]: https://techcrunch.com/2019/02/26/heres-why-youre-getting-al...