>Why do some of the most highly-paid people (actors) join a union and join the picket line? Even if you are high performing, joining up with other workers increases your bargaining position.
Perhaps, but there's also a real chance that the union structure you end up with ends up being net negative for top earners. If you're in the top 10%, what makes you think the bottom 90% won't vote for policies that end up redistributing your wages to them?
Also as I said in my other comment[1], whether this is actually true is irrelevant. All that matters is that it sounds plausible and some fraction of people believe it. Perception is reality in this case.
[1] https://news.ycombinator.com/item?id=37942073
