One clever plan to do that I've heard is the idea of a progressive consumption tax. That is, you have the existing income tax structure but you make all saving

One clever plan to do that I've heard is the idea of a progressive consumption tax. That is, you have the existing income tax structure but you make all savings in banks or brokerages or whatever tax deductible but tax anything you withdraw from them as regular income. This would tend to have some nice properties with letting people smooth consumption, getting rid of special items in our tax code for particular sorts of savings, and solve the problem of billionaires borrowing against their stock to live without having to pay taxes. You do have to keep having a special case for housing which is both a form of consumption and a savings vehicle and a few others but it looks like it would be a bit simpler and fairer.