How would a week's mandatory training be prohibitive?

My profession (as a lawyer) required 5 years of mandatory university education and 3 years of practical training and supplementary courses and exams. Other professions require even more. Every year I must take what amounts to 2-3 days of additional courses to maintain my license.

And I just push papers and money around. I don't move people. Nobody gets killed if I do a bad job.

I think it's only fair to require a tiny bit of training for a taxi driver, also if he works for Uber.