40% is probably on the lower end. I've heard higher tax brackets are over 50%, or even nearing 60% in some EU countries.

I understand where these Quora commenters come from. From my experience living in the EU more than 10 years ago, this model has worked quite well for many years. I was ok too, to pay this kind of taxes at the time.

Now these social models are being tested and strained due to decreasing population, increasing immigration, economic hardships, and basically the fact that the EU has benefited from a colonial past, which prevails to this date, to become a stronghold in the West. Several other reasons, too. Such social models may work well when the economy is good, but come under high scrutiny when times are hard. Only time will tell if these models are reaching their limits and indeed, a new financial paradigm is needed (through Bitcoin?).

I am simplifying of course and I'm sure better-informed people will correct me on some technicalities.

Lots of people have known only such a social environment, and as long as they are not suffering too much in bad economic times, will see the benefits and be ok with paying such taxes. Social welfare feels good when it works as intended. You are making enough money to sustain yourself, you realize your privileged position in society comes at the cost of the less fortunate, and so you are ok that your taxes help the less fortunate. If you are less fortunate, you pay less taxes, and you are happy such a system is in place. Many people grow up with these ideas taught by their parents, and so that's what they consider normal. Even in very capitalist Korea, people are happy about the single-payer healthcare system.

Now, lots of people in the EU do not benefit from these models, and as such, realize the weaknesses they carry. They thus rightfully question the future of these models. Especially in times when their sustainability becomes less and less sure.