"It is not very difficult for high income earners to pay proportionally less than lower income earners."

It is nigh on impossible.

And the data from Stats Canada/ CRA shows it doesn't happen - every analysis of Income tax data in Canada shows that out Progressive taxation system takes a larger and larger cut as salaries rise.

The comments you post don't support your argument in the slightest. Drucker may say that top salaries should not exceed 20X, but that doesn't have any bearing on whether higher income earners in the 53% tax bracket pay a higher proportion as taxes than those who pay zero tax