I think it is due to the wide disparity between potential members.

For example, consider an agricultural co-op, e.g. wheat growers. The members of the co-op have farms of differing sizes, use similar techniques, have more or less comparable conditions. They produce grain which has a commodity level set price. The main differentiator between members of the co-op is the volume of grain they produce. But on the basis of the commodity pricing it is a relatively level playing field.

Now consider any tech company. Products have vastly different pricing - ranging from free to millions of $ (or whatever your currency) for enterprise levels. The "producers" vary in capability from newbies to rock-star programmers. Plus you need management to facilitate communications, etc. Everywhere you look, you find disparity.

The closest you get to a tech co-op is a startup with a small group of people who respect one another's contribution and follow a shared vision. Unfortunately as soon as you introduce outside investors inequality seeps in.