It's denying reality to believe that EU devs are even with US devs financially. I have no horse in this race, I just care about the truth.
I use the US as an example of COL difference not being proportional to salary difference because it's the most egregious example.
If you had looked at the BLS data you would have seen that both the mean and median are $120k, so the argument of rural COL and SV salaries doesn't hold: https://www.bls.gov/oes/current/oes151252.htm.
If you want to compare tech hubs it's extremely simple: look at https://levels.fyi and compare locations.
SF: https://www.levels.fyi/t/software-engineer/locations/san-fra...
NY: https://www.levels.fyi/t/software-engineer/locations/new-yor...
London: https://www.levels.fyi/t/software-engineer/locations/london-...
Berlin: https://www.levels.fyi/t/software-engineer/locations/berlin-...
> But if you were to compare the largest tech hub in America to the largest tech hub in England, you might find London comes out cheaper
Yes, but the salaries in tech hubs in US are nuts compared to London. Especially on the high end.