I personally tend to think that I'd value ride sharing services even if prices increase to parity with traditional taxis. After all, just getting a cab in many cities is a real pain point. I also think that ride sharing services are here to stay, and that both individual consumers and society as a whole are better off for it.

However, the parents point is more general and I think you're talking past it. You can't evaluate Uber's societal contributions based on short term and possibly ephemeral benefits. For example, if ride sharing services suddenly disintegrate once VC funding dries up then they can't be said to have made a meaningful impact. Sustainability is actually crucial.