Your forgetting that the floor is falling because the ceiling is rising.
No, the floor is falling because Americans lose up to 60% of their income to the government. Not just from taxes, either. Things like Obamacare too. What's the point of the government raising minimum wage so that a handful of people can walk away with an extra $100 in their monthly paycheck, if you're going to force them to spend $200 a month on health insurance they neither want nor need?
So a couple making $50K/yr loose $25K/yr to the government? Sure.
The exact amount depends on the state and individual circumstances. As you'll note, said
up to 60% of their income.
Add up the federal, state, and local income taxes. Also add in payroll taxes. Then, add sales taxes. Don't forget about those surcharge taxes on your cable and phone bills. Add excises, like gas taxes and sin taxes. Finally, add in government mandates spending, such as the health insurance mandate. And we haven't even begun to touch property taxes.
The result is up to 60% of the money you earned over the course of a year goes to the government in the form of taxation, or is forced out of your possession by mandate.