I think Cory is going a little too harsh on Uber/Amazon. People use them because they provide convenience and ease-of-use, and are willing to pay for a better customer experience. If anything, 'taxi medallions' are literally the original form of feudalism and collecting rent from doing nothing.
This is a worthwhile talking point. There was nothing holding back taxi companies from building an uber-like experience, just there was no incentive to do so.
Uber took advantage of that opportunity to spin up an exploitative business that did an end-run around existing regulation of that industry.
All that said - many cab companies now have uber-like apps.
I don't feel bad for the cab companies particularly; there's too many damn cars in big cities. That's a city planning problem. I do feel sorry for all the drivers out there, as it's a tough gig no matter who you're working for.