Why should Amazon get to deduct money they invest into themselves? Think about the expense of automation, its an investment that will make them more profitable, suppress wages, and possibly cost someone their job. Why is automation a tax deduction but wages are a tax burden?
You're too focused on retained earnings and you're ignoring the fact that companies like amazon get to grow in a tax free environment as long as they reinvest, while individuals get taxed before they make the money, when they make money and when they spend the money. Imagine what your tax burden would look like if you only had to report the retained earnings of how much your savings account grew.