Doctors incorporating - or not ... 
" .... That is the question. Whether 'tis nobler to avoid taxes than to pay them .... "
The government(s) could not afford to increase a doctor's pay so provided tax incentives instead that increased retained income, a raise by at other name ! They thereby collected less tax $$ and thus ended up with less money, anyway - the same position in other words - had they increased pay but left the tax system alone ( +/- ).
No wonder they teach Discovery Math  .-)
The bottom line is that this is a political shell game designed to obfuscate !

As an afterthought: Why do our MSM and investigative journalists never clarify exactly what it takes in terms of expense to run a private ( typical ) doctor's office/clinic ?! We hear whinges about gross $$$$billings but never take home net or hours worked. Or years of study ...
Me - I would never spend the years of university, internship and $$$$ to become a doctor in Canada !