For those who don't know, in the US in many cities taxicabs use a transferable licensing system (aka "medallion"), with artificially limited supply:
Most medallion owners never interact with the public. Their cash flow doesn’t come from passenger fares; it comes from lease fees that drivers pay to access medallions and the vehicles they are attached to. This means that a medallion owner’s bottom line is largely unchanged whether a driver leasing his medallion gives 20 rides this week or 200.
This is not how the industry has always been structured. And it’s not how taxis operate in Washington, a freewheeling market without medallions where more than 100 companies operate, or in Baltimore, a city with limited cab licenses but no property right attached to them.
The industry shifted in two major ways in the second half of the 20th century: Cab companies turned drivers into independent contractors, and cities allowed medallions to be leased to cabbies for a fee. Today, medallion managers serve much the same function as property managers in the residential rental industry: A hands-off investor with many medallions can hire a management company to find drivers to lease them.
Also according to a 2019 NYT piece, there has been a bubble in medallion prices, which recently burst, resulting in driver suicides etc.
Banks and loosely regulated private lenders wrote risky loans and encouraged frequent refinancing; drivers took on debt they could not afford, under terms they often did not understand. [...]
The combination of easy money, eager borrowers and the lure of a rare asset helped prices soar far above what medallions were really worth. Some industry leaders fed the frenzy by purposefully overpaying for medallions in order to inflate prices, The Times found. [...]
The medallion bubble burst in late 2014. Uber and Lyft may have hastened the crisis, but virtually all of the hundreds of industry veterans interviewed for this article, including many lenders, said inflated prices and risky lending practices would have caused a collapse even if ride-hailing had never been invented.
At the market’s height, medallion buyers were typically earning about $5,000 a month and paying about $4,500 to their loans, according to an analysis by The Times of city data and loan documents. Many owners could make their payments only by refinancing when medallion values increased, which was unsustainable, some loan officers said.
City data shows that since Uber entered New York in 2011, yellow cab revenue has decreased by about 10 percent per cab, a significant bite for low-earning drivers but a small drop compared with medallion values, which initially rose and then fell by 90 percent.
Has this transferable medallion system (with limited supply) been backed by a political party in particular? Given that it is used in big cities, I would guess it was backed by Democrats, but then Baltimore or DC are Democratic strongholds too. Is there a "wing" of the Democratic party that favored this type of solution?