If we gave the means of production to the workers, there would be an immediate increase of living standards. This would also create more democracy in the country, because the workers would have more control over the day to day going ons of their career. This could increase happiness, and help equalize wages.
Workers owning means of production is stupid. Now, for all the middle-class socialist brats from suburban families, who who have never really had to work, congratulations, you've won. What now?
Who would lead the workers? Who would determine salaries? Who would keep the currency from inflating out of control because of the increased salaries?
Why would it have to be society-wide? Couldn't someone just make a company where every employee owns exactly one share? If it worked, everyone would be running it like that. So the question here is: Why?
Well, obviously, it would be less profitable, and that's important, because it would be less attractive to investors, and a company without investors is a dead company.