The process of capitalism is 50 different companies making 8 different shampoos each consolidating down into 1 monopoly that makes everything that survives the market pressures.
At this point capitalism has efficiently discovered exactly which products are left over that people actually want and the company can be acceptably state-owned with zero issues as to product range.
Socialist use of markets should be to use them to produce this outcome with all consumer goods, do not fight the process of monopoly, instead allow it to take place then nationalise after the process has fully run its course.
Markets are really good at this shit. When a new product is invented markets should be used to carry out this process to turn that new product into 50 competing variants until the survivors of the market battle royale get to be the socialist products.
I have not actually thought this through at all I typed it as I thunk it. I'm hitting the post button and immediately going to bed. 