Actually it is like they suddenly have to pay much higher taxes, why do you think people are so upset?  They weren't already paying 48% on that 'extra patient'.  That extra money was being saved for retirement in the corporation, and will be worth a far deal more when it is pulled out, presumably when the physician has a much lower overall income.  

Now if there was a boost in RRSP space, then this disincentive could be offset.