Apparently so, at least if we compare minimum salaries.
But there’s considerable action underway to give minor-league baseball players a living wage. In their case, the money to boost their pay into the $30K-$40K range is certainly there.
NWSL players now make more than AAA baseball players?
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Duresport.com 
The NWSL is a top-level professional league, and probably the most competitive women’s soccer league in the world. Its players include many Olympians and national representatives of their countries. Not clear how that compares to a developmental league in which players are explicitly NOT at the top of their game yet.
It’s surprising in the sense that AAA baseball has been around forever, and it’s less of a developmental league for players on the way up and more of a reserve team for players who yo-yo between the majors and minors. (Which, in a sense, makes the salaries more palatable — if they get called up to the majors for a few days, they’ll make a ton of money.)
Minor-league sports often have national representatives, too. Granted, they’re from the relative minnows. An AHL player might be on his national team in hockey.
And so this is more of a demonstration of how big the gap between the haves and have-nots can be in some other sports. We often gasp in soccer when we see the 26th player on an MLS team making 1% of what the top player is making. In baseball, that gap is even wider.