I think some of them might come out ahead. On the other hand, when you consider vet bills, high cost of quality pet food nowadays, etc., it can cost a pretty penny to foster a pet and get it in good enough health to adopt out, complete with up-to-date shots. So some are probably not profitable, while others might well be profit makers. Some of the regular animal shelters charge a lot for kittens and puppies, but include a vet gift certificate for free spay/neuter and any shots they still need, so the cost really isn’t that high.
Some of the breed-specific rescues charge outrageous fees (around $600+) and run around grabbing every dog of that breed they can find out of regular shelters so they can resell them, and don’t appear to spend much money at all on them. I really wonder about those. A few charge around $250, but spend a lot on vet teeth cleaning (expensive!) grooming, etc., too, and probably operate at a loss or barely break even.
The animal shelter in my town always has gobs of Pit Bulls and Pit Bull mixes, a couple of elderly chihuahuas, no other type dogs, not even mutts that are not part Pit Bull. Hmm. I sometimes wonder whether the other dogs are adopted out so fast they don’t get advertised or whether these rescues are grabbing the others or what. Hmm. Surely it can’t be there are no other type dogs needing homes.
In my city, the “rescue” will go in to the spca and grab any dog under 30 pounds before the public even sees them. Then they “adopt” them out, with prices starting at $400 and I have seen a French bulldog for $900. (No papers, mind you.) on top of that, they make you jump through hoops in an utterly ridiculous process. No thank you. I will purchase my next pug from a breeder, whether it’s backyard or not.