To expand on the point, the purpose of income taxes is to force the broadest shoulders to bear the largest burden. Whether you feel it's ethical to do so, for the purpose of the discussion we say it's OK - after all we can point to many cases where things were earned by means other than hard work.
Things like payroll, VAT and business rates are based on some kind of consumption and are independent of the magnitude of your success. Changing the tax on these things will probably control how successful/profitable you are, meaning if you set it too high your revenue drops off from businesses failing - so clearly you can't optimise on consumption taxes alone. Hence the need to also tax success in some way.
Unfortunately, taxing a very direct measure of success (income) doesn't work. What alternatives do we have? This is the key question.
Things like payroll, VAT and business rates are based on some kind of consumption and are independent of the magnitude of your success. Changing the tax on these things will probably control how successful/profitable you are, meaning if you set it too high your revenue drops off from businesses failing - so clearly you can't optimise on consumption taxes alone. Hence the need to also tax success in some way.
Unfortunately, taxing a very direct measure of success (income) doesn't work. What alternatives do we have? This is the key question.