If the government wants a tax to be paid they need to make it simple and unconditional. If there are loopholes or ways to legally avoid it, they will be discovered and people will take advantage of them.
you could make an argument that in order to optimise your taxes, you have to be quite wealthy to begin with (hiring a tax guy, etc.) - otherwise you don't have any time left in the day to run your business.
so in practice, the little guy winds up just paying the 'sticker price' so to speak, while the big guy has pros who can make their big profits even bigger.
Another way of thinking about this is that the wealthy person is incentivized to invest their wealth directly into higher-risk, economy-boosting activities like starting businesses that (if successful) create jobs that then pay income taxes. Ideally tax revenue is generated from this incentive. The wealthy person could just buy gold bars and create no jobs that generate income tax, but they don't get as good a tax deal on that.