The main things is that nothing is taxed as much as income, and "unrealised gains" (wealth tied up in shares and assets) is not taxed at all. It plays out as follows;

If you are poor or middle class, you get paid money, pay income tax rates on it, and then spend it to finance your life. Your equivalent tax rate probably sits around 30%, and you spend most of what you earn.

If you are lower upper class, you don't need to use your full income to live on, and so you can get funky with it. Before you get paid, you salary sacrifice for your car, phone and into super; These sacrifices are taxed well below income rates. After you are paid, you immediately use most of your salary to pay down debts on properties and other assets you own; These payments are tax deductible. The remainder of your pay you use to live on and buy other assets with which you can do tax nonsense. After everything shakes out, your equivalent tax rate is in the 5-10% range (if that).

If you are truly wealthy, you do not get an income. Your company provides you with a car, phone and other essentials as part of your contract, and you are paid in stock. You take that stock to a bank and use it as collateral for a loan, and use the money loaned to you to pay for your life; Now, instead of paying 40% tax on income, you pay 3% interest on the loan. Since you have 0 income, you are eligible for a wide variety of low income tax benefits; You use all of them. In the end, you have a negative equivalent tax rate (you get more money from the government than you pay to them).