system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why can't taxi drivers just become Uber drivers?
gpt
I work in banking in New York City, and the answer for here is that there are high barriers to exit for cab drivers. In order to operate a taxi in NYC, you need a taxi medallion, which costs around a million dollars. Obviously these drivers take out loans for the medallion, but they're still locked into this debt payment until they either (A) pay it off, or (B) sell their medallion.  The problem with 'B' is that the value of these medallions are declining as a result of uber (they'd need cash to pay off their balance to be free of the loan, and by extension, their link to the taxi cab).  You can even short (finance term) the medallions on exchanges; it trades under TAXI. 

Analogous to why to home owners locked into a home with negative equity during the housing crisis, except they were willing to take the foreclosure loss. 

Edited for words.