[TheOtherHobbes]

I wouldn't say it's trivial for a competitor to take over.

The Uber app is still best-in-class, and all my friends now say "Get an uber" instead of "Get a cab" because the UX is so much smoother.

Generally it's extremely difficult to dislodge an incumbent from a market slot. Newcomers can only compete on price, UX, and brand recognition. Ideally all three need to be significantly better than the incumbent to have a hope of taking over. Without all three the best a newcomer can hope for is a small slice of the pie.

So market share definitely has value in the abstract. Unfortunately in Uber's case it has negative economic value because of the costs/subsidies.

Then again I suppose it's possible Uber has always been a cunning plot to take VC money and spend it on subsidised transport. If so, it's definitely been a success - for now, at least.