As we all know, the Trump administration’s tax reform reduced the tax rates, eliminated the deduction of state and local taxes (SALT), and increased the standard deductions.
The elimination of the SALT deduction negatively affects more rich people than poor people. Most poor people use a standard deduction, so they do not deduct their state and local taxes.
If SALT is more than 6.6 percent, very rich people will pay more to the federal government. For residents of New York City, this combined tax is 12.6 percent
I think that it would be interesting if the IRS computes not just the amount of a taxpayer's current federal income tax, but for comparison the amount of their federal income tax using the old tax rates.
Of course, it can be done only if a taxpayer uses the standard deduction, but most taxpayers do not itemize. This information could be given to an individual taxpayer on request.