Are you talking about eliminating every social program that helps low income folks? Are you talking about getting rid the earned income credit? The low income do have an investment in the game. It is called putting food on the table.

You could soften the blow on low income people by getting rid of social security, and Medicare taxes. You treat them like any other item in the budget funded by income taxes. You just reduced the national debt by 5.1 trillion dollars. There would be no need for the Social Security Trust Fund. You just increased the tax on people making over the social security maximum by 6.2%.

A flat tax based upon gross income would destroy the housing market. How many people bought their house with the assumption that property tax, and mortgage interest were deductible on their income taxes? Take away these deductions they can't pay their mortgage. The housing market would be flooded. Housing prices drop, and you have a banking crises to equal or worse then the 2008 great recession.

Simple solution to a complex problem never works.