The irony of the phrase "workers of the world, unite!" is that, in capitalist countries (by that I mean relatively free market systems), workers are better off than in non-capitalist (less free market) systems.
Like... Yeah... Unite to make things better for workers... By supporting capitalism.
Private sector unions and such ain't inherently bad, but anti-capitalist rhetoric that hinges on that phrase promoted in the communist manifesto seems to me to be a promotion of capitalism rather than a critique given the knowledge history has given about the actual practice of systems irl.
I feel like if Marx was alive during a time when workers could readily buy shares in their employers and other companies, he would have different opinions about both capitalism and communism.
Like, hey workers, you can own the means of production now! And the barrier to it is very low!
Not like back during Marx's time when most workers were totally shut out of being able to own the means of production.
At best they could own tools of their trade, but not a share of a factory.