You can make credits from male "milk", why not breast milk?
I'm pretty sure the payout for cum was reduced at least twice. It's certainly not as profitable as it used to be (I seem to recall reports of easily making millions). The Male Milker on New Texas has a limit you can get per session and will break if Steele produces more cum than what would give maximum earnings. I don't know about Breedwell. Steele also isn't paid when getting the blowjob with Carrie instead using of the machine.
It's all but stated that milked sperm is used to get people pregnant (like a sperm bank of sorts)...
I'm reasonably certain at least some of it goes to Breedwell. Or at least gets their attention.
While it's reasonable to assume that the barn's main purpose is to collect and process New Texan cow-girl milk for exportation, Steele being a non-citizen (and possibly also being non-Treated and/or lactating something other than milk) could mean that their breast milk doesn't pass the usual QA standards in place...
Steele lands at Big T's Ranch. As a Tourist attraction, the Barn might have a much higher count of non-New Texans getting milked there (Millie offers a Faux-Treatment), resulting in a different destination for the milk than at other milkers on the planet.
...alternatively, the milkers Steele can access might be more of a public relief amenity than anything profitable. If either of these are the case, whatever is milked out is likely either discarded or used for some purpose that doesn't generate enough of a profit to warrant paying Steele...
There's a question: Are New Texans normally paid for their milk, or is the milking itself considered reward enough?
That said, on Dhaal, milk is a valuable product. To the point that the first enemy added was the Milk Thief(ves?). I doubt they're stealing it all for personal use. I was hoping for a victory scene where Steele gets milked by the Thief, but they have to pay. Or Steele could sell to a Milk Bar. After Zheng Shi's Blackjack, inflation clearly isn't a concern.
If Reaha is still paying off her debt by selling milk, she should probably earn more while on Dhaal, but I don't think that's currently taken into account.