I computed Italian GDP per hour worked at 93% of the US's, but Italians work 25% fewer hours per capita, thus GDP per capita is ca. 70% of the US's.
Then if you consider that Italians pay 15% more of GDP in taxes, the per capita private product remaining in households in Italy is only ca. 55% of the US's.
Thus, in terms of value added per hour, Italian productivity is comparable to the US's, but in terms of private income in households, American incomes are nearly double of Italian levels.
It's funny that the people saying European living standards have remained comparable to US ones are in the US (Krugman, Dube), while those saying the opposite are in Europe (Garicano, Aghion, Bergeaud).
European social democracy is a romantic ideal to the American left. They don't want to admit it's failing. Unfortunately, if you live here, you can't help but notice the cracks, even through rose tinted glasses.