Continuing the discussion from Charity to leave money to?:
As this is not on-topic for the thread that spawned it, I’m replying in a linked thread.
I guess it depends what the pet is being treated for. As i mentioned previously, a shelter isn’t going to pay for chemotherapy for an animal dying of cancer. And once, we were fostering a kitten that we found unresponsive on the bathroom floor. It needed a day of IV fluids and similar high-tech supportive care, and the shelter said they couldn’t afford that. They gave us permission to pay for the care, or they would pay to have the kitten humanely euthanized. Mostly because my kids were emotionally involved with the kitten, we paid for the care (about $1k) and the kitten recovered. After it survived the night and seemed more stable, we took it out of the emergency care hospital and took it to one of the regular shelter vets (our vet, as it happened, but selected by the shelter) who diagnosed a likely respiratory bug that got into the brain, and gave it cheap antibiotics, which seemed to help. The kitten then got supportive care at our home (provided by us) and mostly recovered.
So no, shelters here don’t pay for expensive procedures, either. But most of the bread-and-butter care, like immunizations, spay-neuter, treatment for parasites, antibiotics, are provided by the same vets who offer the same care to pets. I don’t think it’s any more “assembly line” than the primary care that pets get.