Does the medical working world ever have to worry about being unemployed (outsourced, replaced by automation, downsized, etc.) or collecting for services rendered (cheque doesn't clear, delayed payment, etc).

For the record, I do believe some of the professional class (i.e. not dentists - they can cash out by selling their practice)  and small business owners should be allowed to shelter passive income, but there should be an annual cap on the amount that benefits from a lower tax rate.  The annual amount should be greater for the non-professional business owner as they face greater risk (competition, technological, political, etc.).   Now that I think about it, the professional class needs a range as accountants and lawyers face risks that doctors do not.