It's a business model problem; The "Uber" business model relies on a monopoly.

The business model is 1) "Have artificially low prices to push all competing business into bankrupty", 2) "Now that we're a monopoly, raise prices massively", 3) Massive profit, so long as no government starts doing anything about the fact that both steps #1 and #2 are illegal.

That business model fails the moment you have multiple startups dumping the market, none can move to step #2 because they'd bleed all their users to whichever competitor is still in step #1.