yes, essentially. but unions have to control a significant part of the market to be able to make significant demands. a rising tide lifts all boats, but the moon has to actually pull...
I can see how right-to-work laws undermine that gravitational "pull". But do you reject the possibility of legitimate reasons for wanting to benefit from union wages but not be part of the union itself? Political reasons, for example: unions may make campaign contributions to candidates the worker does not support, or they may hold positions that worker finds abominable (personally, the anti-immigrant stance and rhetoric of some prominent unions makes me sick). I can see why freeloading is unfair; but it seems equally unfair for a worker to be denied a more liveable wage for political reasons.
'freeloading' is unavoidable in the context of the wider market but there is no reason to prevent employers from signing exclusivity contracts and it's absurd to force unions to provide real services to people that explicitly choose to not support or participate in the union.