Actually, there are significant legal obstacles. It took around 200 years to create good legal framework and regulations around publicly-traded corporations, so

Actually, there are significant legal obstacles. It took around 200 years to create good legal framework and regulations around publicly-traded corporations, so that for example, when you invest, you can make sure you won't get scammed. (And it's still not perfect.) Worker collectives, because they are uncommon, and do not operate under well-known legal framework, face significant obstacles in, for example, getting loans.