The Social Security Wage Base is $118k, so someone making between about $38k and $118k actually pays 31%-34% on the upper portion of their income, and someone making $119k pays 28% on the upper portion of their income (the part above $118k) until they hit the $192k (33%) bracket (at which point they're still paying less). It isn't until you hit $417k that you enter a tax bracket (35%, with the 39.6% bracket at $419k) above the total Federal income tax (OASDI+general) imposed on the middle-class.
Note that payroll also has to fork out an additional 6.2% of OASDI, meaning the price of products must factor in the employee's base wage as the stated wage plus 6.2% to include Federal income and OASDI taxes. Executives tend to make $20-$50 per employee, so those high-powered salaries represent $0.01-$0.025 per hour; whereas the hidden portion of the 12.4% OASDI tax represents $1.674/hr for the median $54,000 income worker.
You can deduct contributions to your 401(k), IRA, and HSA; you can't deduct OASDI, and you can't deduct from OASDI. You also pay for OASDI and income tax out of production--you work some labor hours, you make wage for those hours, that represents wealth (things are made), and a portion of those things (the buying power of your income is things made for that income, essentially) is taken to build roads or pay welfare. OASDI is itself also taxed as income, yet isn't tied to production; instead, that portion of income is double-taxed, once when a good or service is produced via labor (income on wages), and again when that money is handed out to retirees (income on money not applied to any productive work). The same is true of welfare. Money isn't magic, and is directly backed by the productive output of the labor for which wage is paid; that representation is distorted when welfare is taxed as income. Obviously, if you paid tax-free into 401(k), that wage came from labor but wasn't taxed (yet), so should be considered income when taken as distribution.
Tax systems and monetary policies are complex. I constantly argue for a Universal Social Security as an untaxed benefit fed by a dedicated flat tax in parallel to a general fund for the above reasons. Besides that such a system would necessarily take and distribute a percentage of the per-capita buying power (takes it as a USS tax alongside the general progressive income tax; redistributes it flat and untaxed), it also allows us to flatten out that middle-class tax peak without raising taxes on anyone.
The very-poor can't live the high life in NYC or SF on that, and they don't really do that today; they'd have a minimum income on which to live, and any work would dramatically improve their quality-of-life without the threat of losing their welfare income as in today's system. OASDI is easy to grandfather, easy to replace with savings (the people who can't save also don't receive OASDI today), and eventually overtaken by the growing purchasing power of the USS (trade and technical progress means it grows in buying power). Minimum wage loses its importance because everyone has an income which automatically adjusts for actual buying power--which means it grows faster than inflation--and can refuse to work for unfairly-low wages, since life sucks living in a tiny apartment with meager comforts, but life is also stable and doesn't involve freezing to death in the winter while fighting over trash with the rats.
By the by, sales tax is complete trash. Sales-taxable-income represents a smaller proportion of an individual's income when he buys services and securities than when he buys tangible goods; thus the rich pay the same tax rate on less of their income, thus pay what amounts to a lower proportion of their income in taxes. The poor pay a greater proportion of their income in sales taxes. That makes it analogous to an income tax in which the poorest pay the highest rates and the richest pay the lowest. On top of that, it directly raises the sale price of goods without raising incomes, thus reducing the number of goods purchaseable across the entire consumer base, reducing the number of jobs supportable from the revenues of those sales. Fire your representatives, and keep firing them until they repeal that horse shit.