Underpaid compared to what? If people are willing to do the work to a high professional standard for a certain wage, than that is the right compensation for that job. When you setup arbitrary fair wages above market, you must also somehow protect them from intruders from other fields willing to change jobs and benefit from the higher wages in your field. This is exactly what a co-op ends up doing most of the time - if they don't succumb to a traditional model where the initial members become the owners and the later employees have regular employment contracts.