UK seems worse, but other EU countries actually gone down, for instance France has had a big drop since the 50's.
The existence of a 100 people with 100 billion each really does nothing for the real purchasing power of the middle and lower class. Income inequality is a red herring designed to act as a political wedge and distract you from a failing government.
It has many deleterious effects but the most visceral one is that it prices them out of the housing market. Those 100 people's purchasing power distorts the hell out of any market they dive into and real estate is very much one of their favorites.
Taxing them and all the people with wealth close to them to hell and back would make the real estate market sane again even if the tax money wasnt used to build new housing (which it should be).
Wealth inequality is the real killer though, and the measure that is the most out of whack. I The rule is that if you ever want to downplay how bad things are, focus on income inequality to the exclusion of wealth inequality.
It doesn't much matter if everyone lives in a 2-bedroom house and rides a bicycle to work, or in a 5-bedroom McMansion and drives a Lexus. DDG for "hedonistic adaptation." Or travel to poorer countries.
What does matter is /stress/.
Right now, most Americans seem to be living in a state of high financial stress. Baseline costs, e.g. college debt, housing costs, medical costs, and similar take a majority of people's income. The remaining disposable income might buy more computers and TVs than in 1950, but that doesn't matter much.
What does matter is that, for example, the short-term job loss, a litigation, a divorce, or a medical problem can lead to cascading financial ruin. It matters that the cost of raising kids puts having a family out-of-reach for many, or just very, very hard.
The economy in, for example, the Soviet systems was far poorer, but on the whole, everyone was guaranteed housing, food, and basic medical. People were happy enough.
I have mixed thoughts on universal basic income, but as I get older, I find concepts like that more and more appealing (personally, I'm more a fan of universal basic food, medicine, and housing, with all the complexities that entails). I also find Chinese-style socialization of land and of finance more appealing.
Concepts like this date back to Rome. The poor in Rome were guaranteed grain: https://en.wikipedia.org/wiki/Cura_Annonae
Poor people and even the median did indeed become poorer, as wages either stagnated or even declined in real terms. Some consumer goods particularly electronics have decreased in price, but essentials have not: they increased a little (food) to a lot (housing, healthcare).
Poor people did not become poorer and incomes did not stagnate if you include benefits. Currently healthcare is more expensive, and a larger percentage of total compensation is given in health benefits.
Doesn't matter what your view on the health care issue is, if you're an employer, you spend more on your employees now than before
Which one makes for a successful society?
You couldn't have an MRI in 1970 because your hospital didn't have it. The technology of health care is now a lot more advanced and can add years to your health expectancy.
Now, there are government programs that help you pay premiums or give you free care. I was on Medicaid several years ago, so the poorest people don't have the issue of not being able to pay.
But that's a whole another topic. The point is you can't just compare what you can afford, because you're not comparing the same things. Houses are bigger these days as well.