How? Labour has all the voting power, capital only wins if they can manipulate labour to vote against its own interests like they managed in USA.
And plus, even if the "pro-labor" leader would win elections, there's nothing that forbid him/her from following up on the election promises till the end of his/her term. They can just do whatever their campaign donors/lobbyists pay them to do as once their political career is over, they'll have a cushy job guaranteed in the private sector enterprises they "helped" during their term. It's the classic political-private sector revolving dor.
Case in point, all EU leader have promised to tackle housing, and yet, during their terms, housing has gotten more and more out of reach with each passing year, proving that your voted leaders are not on your side, they just claim they are to win your votes. German and Austrian politicians who helped kill nuclear, took major lucrative jobs in Russian oil and gas companies afterwards. The list can go on. We basically have legalized high level corruption.
Pay in the US is attractive, but doesn't make up for what you lose from being in many European countries. Health care, public transport, well maintained roads, better work-life balance, more vacation time, less poverty, won't get murdered in a mass shooting etc. Your mobility as a citizen in the EU is excellent as well, free to travel to so many different cultures.
I live in the UK, and this country is probably going to get much worse. But I still wouldn't trade it just for a higher US salary.
Some in Europe were labour was manipulated to vote for migration-friendly parties. Although now this seems to be changing with growing economically left but anti-immigration so-called „right wing“ parties.