"Right-to-work" laws are effectively "duty-to-undercut-other-worker" laws. Right-to-work states are nightmares for working people who have lower pay, employees less likely to have medical coverage, more deaths on the job, lower credit scores, lower educational achievement, and more high-school dropouts. They are poorer. The only compensation is that duty-to-undercut states have lower costs of living... which may reflect the higher real-estate costs in such states as Hawaii, California, Illinois, Massachusetts, New York, Pennsylvania, and Maryland. There may be more jobs but they are lower-paying, dead-end jobs.
It's hardly surprising that lower labor costs would be associated with a lower cost of living, but since the difference in the cost of living between the two groups of states is greater than the difference in hourly wages it seems to me the lower wages are because of the lower cost of living rather than the reverse as you are assuming. Indeed, given the pitiful rates of private union membership in both States that permit the agency shop and those that ban it, I'm skeptical that right-to-work legislation has much of an effect on wages or working conditions.
Outside oligopolistic industries (at one time the auto companies and big steel companies, and probably still Boeing), monopolistic ones (some transportation, utility and of course government entities), unions have almost no impact on employee compensation. The market where there is competition is a harsh mistress. It will not allow a company to stay in business if one pays workers much above market.
