free market policies. Proper Co-ops are designed not to exploit workers, local resources or destroy communities in order to create profit therefore have a hard time competing with ruthless profit-oriented companies in most markets. Co-ops create social value and are beneficial to workers and society alike, but they need to be nurtured actively.
On the other hand, less free market - which is what you get when you allow monopolies and oligopolies to dominate it - is harmful to them, just like any other business that's not "big enough".