Taxes are paid on profits, not gross revenue. If my company makes $1M net but I decide to expand my business by buying more equipment or staffing up I can spend that $1M on that and have a net of $0 profit and owe $0 in taxes.
Explain how by lowering the tax rate from 35% to 15% gives me any more money to expand my business when it is taxed on profit, which I could choose to reinvest as much as I want when I want and write it down (current, past or future years)?
All it does it does is it means when I have no where else to spend my profits that it shows up on the balance sheets as profit. Do you know who benefits from that? Shareholders, execs and board members.
All of that extra money will just get locked up in the bank accounts of the people who already can't figure out how to spend the money they already have. It does not create more revenue for the govt, it does not accelerate growth.
History has shown time and again supply side economics does not work. It's not just a theory, the Laffer Curve has been proven to be nonsense as much as it can outside of a vacuum.
The reason the wealthy love the idea is because there are only so many ways to create the growth on the balance sheets that the market demands each year and this would be an easy way to do it.
You think wealth inequality is bad now, wait until you see a 15% Corp tax rate. The people who will pay for the missing trillions in revenue will be the 99% that are already struggling. At some point the system will be too stressed and this could be the proverbial straw.
I would recommend those reflect on the origins of our tax system and how tax was to be derived exclusively from business income and not wages before feeling sympathy for the non-human entity called a corporation.
If you want to see a large influx of growth to the system you force that money to reenter the system. Making it illegal to use shell companies and tax havens purely to reduce tax liability would have injected trillions back into the economy that would have created some great outcomes just based on tax revenues and the need to reduce tax liability thru investment. Read healthcare, education, wages, infrastructure, better jobs, etc.