Then if we cut the rates to zero then the money should come pouring in?
Why would you think that? Could it be that if we increase tax rates to 100%, money would stop coming in? Actually, that is true, the following tax year. Since the government took everything, the economy would collapse, and so the following year no one would be either making a profit, or be able to pay taxes.
Your devil's advocate argument is well taken though. The government suppresses the economy with too much taxation, and at the same time spends way, way, way too much. Much more than it takes in.
So, there has to be an ideal tax rate, that allows the economy to grow, thus increasing the overall size of the GNP, and thus total tax revenue. That rate may be between 17 to 19% of income.
This must be combined with fiscal restraint for the government, in the form of a constitutional Balanced Budget Amendment. Since the Democrat Party is in the business of accruing power and influence by buying votes with tax payer's money, there has always been a political road block to the kind of reform that might avoid the ever increasing debt they and an expanding unaccountable bureaucratic state inevitably burden us with. This is the problem and the solution that will never be understood by those who are immune to real world economics.