Actually they do here as well in the states. My wife and I just had to deal with the rapid loss of our dog to skin cancer.

Her treatments were cheaper than paying a doctor here in cash. Normally I pay a doc $150 or less for a routine walk in with "I have the flu".

Our dog got chemo pills, checkups, hell the vet even called us each week to check her status between treatments cheaper than that $150 I would pay for fifteen minutes of doctor time.