Reposting a relevant comment I wrote a few years ago (although the last paragraph isn't relevant to Amazon warehouse workers specifically): First, culturally,

Reposting a relevant comment I wrote a few years ago (although the last paragraph isn't relevant to Amazon warehouse workers specifically): First, culturally, US Americans are much more individualist than most Europeans. (Obviously I am painting with broad strokes here, but it’s true in a general sense, on average). US Americans are somewhat less likely to feel solidarity or a sense of common cause with coworkers, and more likely to value the freedom to negotiate their contract on their own. They are also much more likely to distrust large organizations and bureaucracy, sometimes to an extreme extent that would be puzzling to Western and Northern Europeans. Rather than being on their side, many would perceive the union as just one more large bureaucracy trying to screw them. Third, there are many current examples of unions in the US that have made industries meaningfully less efficient. And highly-paid US Americans are less likely to see themselves as oppressed by their employers and more likely to see themselves as making common cause: after all, they have a common goal of making a lot of money. If my company, say, found it harder to fire low performers (an almost certain consequence of a union), it would be less efficient, make less profit, and be less able to pay me my current high salary.