Medallions are required because cities regulate taxis prices and policies. Doing so distorts normal market forces. So medallions are a sort of conciliation prize for taxi drivers having the business model dictated. Govenment limits price, but also lowers competition to ensure they can make a profit.

Uber isn't beating some mustached villinous Taxi lobby. They are beating cities who wanted a regulated car service.

I think Uber is probably better than the status quo, but it's not fighting big business, it is big business.