The US having significantly higher productivity than Europe as a whole is a relatively recent phenomenon (since around 2005), and there are a number of individu

The US having significantly higher productivity than Europe as a whole is a relatively recent phenomenon (since around 2005), and there are a number of individual European countries (e.g. France and Germany) that have similar productivity to the US. So I don't think it can be that simple. If having governments that are left of center (by US standards) killed productivity, then we'd see a different historical and present day picture.