Well, we can definitely debate over whether it produces the right incentives or is equitable. But it is certainly more equitable and useful relative to tax breaks for billionaires and corporations.
By "real businesses" I don't mean the likes of Amazon who rarely if ever make a profit. They're not really paying taxes anyway. Neither am I talking about big international corporations, they know how to offshore and not pay taxes as well.
The same goes for billionaires. You can't tax them and expect to get more money. They can allocate their wealth to pay the minimum in taxes.