That has to be inherent to every system since everyone’s contribution is not identical to another’s. I think nobody can make a case for a system free of any inequality. Even in those where free markets ruled by supply and demand is limited.
But still, inequality in the US is getting way worse and it has little to do with standard of living.
Standard of living in western europe is about the same as here in broad lines. But if you look back at 1980, the 1% in the US and in Europe represented about 10% of incomes. In 2016, the 1% was up to 12% of incomes, where as it was up to 20% in the US. That’s a very significant difference.
Sorry, I wasn’t trying to imply that there wasn’t inequality in other systems. The difference is that the people in favor of those systems often claim that there will be no inequality with government/collective ownership of the means of production, yet in reality is has never worked out that way. In capitalism, I think inequality is a feature. You can be rewarded more based on your talents and work ethic which is frowned upon is true marxist systems…
You have to put this caveat in to claim it is getting worse because the standard of living of many of the poorest Americans today is better than the standard of living of many Americans considered middle class 45-70 years ago.