Actually, you only pay the second 50% on what you have left after life's expenditures (mortgage(s), cars, food, insurances, utilities, etc.) so you won't come close to 75% on your overall tax burden.
If the tax burden is really 50%, then you pay for your expenses after having been taxed, and what I wrote is correct. Actually the case is easily made that the tax burden is 50% or more, given that what income you make faces income tax, but of the remaining money, you still pay lots of taxes (e.g. sales tax) with what you spend, and when you pay someone for a job, some of that money goes directly to the government as *their* income tax, and what they spend goes in part to sales taxes. So of the original 100% of money that you made, the government takes a lot of it.