Going to work without a union is like going to court without a lawyer. Are there incompetent lawyers? Does it cost money to hire a lawyer? Of course, but that doesn't mean it isn't a stupid idea to try to represent yourself pro se.
Unfortunately, workers in the US have been the subject to the equivalent of a fifty year propaganda campaign bankrolled by prosecutors (business owners) to convince people they're really better off if they represent themselves in court pro se (without a union). The sad thing is the campaign has worked surprisingly well.
Dropping the analogy, I think many tech workers are treated relatively well for now by employers. Sort of like a well-treated personal assistant to the boss, who is comfortable and has their small privileges compared to those in the factory floor, and therefore feels like they're more like a boss than a worker, even though that's not at all the case.
The startup ecosystem has also encouraged tech workers to think of themselves as future bosses rather than present-day workers, so they favor the policies they imagine their hypothetical future selves benefiting from, even though it hurts themselves and their friends today.