I found this example interesting as a Canadian, as currently there's a big tax battle over people incorporating to avoid high marginal tax rates and take advant

I found this example interesting as a Canadian, as currently there's a big tax battle over people incorporating to avoid high marginal tax rates and take advantage of relatively low small business tax rates, plus income splitting (which normal employees don't have in Canada). In Canada the emergency room physician would be incorporated. Personally I think a lot of the issue is coming from lowering small business tax rates while cranking marginal tax rates federally and provincially.