The majority of cab drivers in Toronto, New York etc are degree holders. Many are immigrants whose academic credentials have not been verified. Some are American or Canadian post graduates. Yes their papers are good for immigration purposes to the west but not good enough for registration/licensing purposes to practice their professions.
I will send you the link to a study about cab drivers in Toronto alone. FYI, over 300 were found to hold PhD.
Full disclosure: I wrote an academic paper on this issue with a very colorful heading but it was too hot for most journals that refused to publish it unless I made changes. I refused because i had interviewed hundreds of immigrants cab drivers so there was nothing to change. The paper was embargoed for 10 years on grounds that I had included govt information which was still under seal.
Let me just say that it is a real waste. Please respect that cab driver you met in New York or Toronto. They are driving cabs because of racism. Yes racism period.
Look at the reports below: