> you can literally start a company with the coworkers you would have unionized with and created security for yourself and them.

I can, but we'd still be taking on a bunch of risk - we'd have to put the capital into the company, as owners we would no longer be eligible for unemployment insurance if the company did fold, we have the possibility of one of us kicking another out so internal politics suddenly matters - when the whole point of the exercise was to get stability even at the cost of some upside.