What's wrong with the factory owner owning the product of the factory is that then he has the power to set wages and prices, the employees do not have equal power to do so. This creates an inequality of power, which means that it is no longer an anarchist situation. The owner is a government.
Kiba already explained perfectly why its not true that the factory owner sets wages. If it were true most employeers in the USA would pay only minimum wage. The reality is that only 4% pay minimum wage.
Now, it is true that government regulations hurt the workers position when negotiating a wage and allows the factory owner to pay less for labor. But this is not a problem of the free market, its a problem of state capitalism or corporate socialism (Ill let you choose the label).
Again, I would like to know why you think its wrong. I agree in a lot of things with socialists, specially mutualists, but I really dont get this obsession with demonizing wages.
Anarcho-communism has also existed, in Ukraine and Spain, in both cases it was destroyed by a military attack, not subverted from within as happened in the American West.
The anarcho-communist communities did not live enough to see what would have happened. How do you interpret that they not were able to organize and defend themselves? Also its important to notice that some of this communities became extremely morally repressive even banning alcohol. In some few cases they even became murderers.
Also, all societies that are capable of lasting die from within. Its human nature. People get used to the institutions that gave them prosperity and take them from granted. Then they start neglecting this institutions assuming the prosperity will last. Its nothing extrange, it happens to all systems because its human nature.
Btw, I dont think the American West as a whole is an example of anarchy. Some regions and some zones in particular were, but not all, although there is no doubt there were freer than today.