but some sources state that the bare minimum salary to be happy in places like Seattle, where these engineers need to be located, is around $117k/year.
Those sources also state that worldwide the number to be minimally happy is $95k. I'm going to assume Europe is at least at the global average and likely a bit above since the US on average is at $105k. So if you go by those studies then the new grad in Seattle making $120k is minimally happy while the seasoned engineer in Germany making $90k is not.
I mean as someone who has experienced both the US and Europe I would say this applies to most everyone posting here.
And if we're going to sling insults then I'll say it's hilariously amusing how clearly fragile the egos of the people posting here are.