Sorry, I must have added the extra bonuses on top of the gross salary that already included them. The 5 210€ figure indeed matches 70k USD.

The first link was ZipRecruiter survey with two peaks at 54k and 150k, leading to the average of 100k.

On the cost of living, I see your point, and sure a straight 33% increase is nothing to sneeze at. The actual impact is more complicated depending on the personal situation, I'm not in the US so I was under the impression there's a lot more costs, especially with a family for instance, where EU countries tend to be costly for singles but easier to deal with with kids. But it also comes down to life style, and researchers might benefit as much of the social perks in general (overall I'm mostly in agreement)