That's like saying Facebook shouldn't be profitable because anyone can come up with a social media platform.

There are user costs to switching platforms, even if the platform is a ride sharing app. I get that the friction is less than something like Facebook, but an amount much, much smaller than 23 billion would have been enough to 1.) have the best app on the market and 2.) advertise/discount where necessary to maintain some market share.

If your customers have an unsustainable business model and you have favorable unit economics and a market leading position, you can quite literally sit on your cash flow (good unit economics and low overhead lets you survive market share losses) and wait until everyone else goes out of business.