These percentages are all subjective, I'm just trying to illustrate a point.

I don't think it does mean a complete takeover. There are plenty of industries where being 10% cheaper doesn't mean you "win", and there are plenty where being 10% better doesn't either. In a world of perfect competition and perfect information it might, but it's well accepted that we do not live in that world.

It's an odd argument to make in the context of Uber/Lyft, which have indeed "won" by any reasonable definition, and handsomely rewarded it's investors (which should be victims in the overhype / under deliver scenario).

Assuming that incumbent does not improve...