Even outside of the tech co.'s, cheaper talent across Europe is a huge factor. I'd also guess its because product teams are also largely centralised in the US,

Even outside of the tech co.'s, cheaper talent across Europe is a huge factor. I'd also guess its because product teams are also largely centralised in the US, meaning development-focused talent is not in the same demand. Similarly, the variety of industries avaialble in cities like London, Berin, Madrid, etc., mean that salaries tend to homogenise across industries, instead of being almost exclusively tech co's. In any case, a base tech salary in London can exceed £100k for manager/engineer lead roles, which is almost 3x the average salary within the city. I wouldn't say that's anything to complain about.