Paying 50% of your salary can be "ok" for a rich person, tough on middle class families with children, and impossible for a poor person (difference between making and not making rent).
This is why tax rates aren't constant for all incomes, they depend on income, costs (family, children, etc.), etc.
My tax rate would be slightly over 40% if I were single, but my partner's income isn't as high (still over >35% taxes), and we have two children. We get taxed as a family, so our incomes kind of get added and divided by four, and then our "family" tax rate is ~30%.
If you earn a lot of money and have no family / children to care for, then you get taxed with the highest rate which is slightly less than 50%.
If that's not your situation, your tax rate will be lower.
Also, there are some ways to delay paying at least a portion of your taxes (e.g. by getting stock compensation, and paying the taxes on the original price of the stock much later when you sell, etc.), which are often used for high paying jobs (somebody working on a dinner doesn't get "stock").
Having said all this, I've payed almost 50% taxes before, and it was ok. My net salary was still way above the median, and the cost of living here is relatively cheap.
The only real difference of this tax systems are (1) all the benefits that you get, and (2) the variable tax-rate widens the middle class significantly: it is harder to become "poorer" if your salary decrease because the tax rate decreases with it, and it is harder to double your net salary because the tax rate grows with salary increases, at least up to the almost 50% limit.
Many of the benefits are just the outcome of having a large number of people that live with 1 job, working 35h/week, and that don't have to look at their bank account ever to see if they'll make it to the end of the month.