Capital gains and interest income are not taxed as long as that income is reinvested. The income is taxed only when it is consumed. The same is true for income derived from labor.
Deductions are no longer a relevant concept under a sales tax.
Taxpayers, not the government, get first crack at their paychecks. There are no deductions from the paycheck, so there is no need for a tax deduction for state and local taxes or for charitable contribution. All goods and services sold at retail are taxed. This way we all know what the cost of government is and can make rational decisions about its value relative to other costs we incur. Otherwise it would be hidden in the retail price of the final product.