The merits of cooperatives opposed to privately owned businesses.
If cooperatives were efficient they would be outperforming privately owned businesses which is, AFAIK is generally not the case.
Actually, they do, marginally. Only something like 3% though. But worker morality is extremely high, feelings of accomplishment and fulfillment are reported across the board, and they at least are able to keep up with privately owned businesses.
https://www.thenation.com/article/worker-cooperatives-are-more-productive-than-normal-companies/
http://www.uk.coop/resources/what-do-we-really-know-about-worker-co-operatives
Wages by and large aren't shrinking. They are stagnant in some income brackets, but this is often compensated for by increased total compensation. Regardless,
https://www.theatlantic.com/business/archive/2015/09/low-income-worker-wage-decline/403840/
Not only is this one hell of a contentious claim (volume and technology improvements make this really hard to substantiate over time in any meaningful sense - bananas might get consistently cheaper but they can be replaced by other, newer, more expensive goods) - this is literally a primary result of competition between firms predicted a long time ago.