The idea that workers in wealthy countries like the United States are part of a “labor aristocracy” bought off with the fruits of imperialism is nonsense. The best way to build a movement against US imperialism is to build the labor movement domestically.
The Starbucks unions are done on a store-by-store basis and corporate finds ways to fire or move around the radicals, so usually they will be around for the vote but won't actually remain at the store without an unfair labor practices win or a pressure campaign like The Memphis 7. Buffalo is pretty good. But random stores, for the most part, are good on social issues but not class conscious nor do they actually organize coherently.
Amazon warehouses are similar in that they are warehouse-by-warehouse. Amazon is more effective at union busting at them and they're not particularly class conscious. They are missed opportunities because American union organizers and lefties don't really have a plan for how to make a union class conscious, they just think if you use the organizer model things will work themselves out or maybe you can co-opt them a bit.
Jane McAlevey is about as good as it gets in the US, and she still pushes a Bernie version of class consciousness.