It may seem exorbitant, but vets in large cities are also paying out the wazoo for rent, staff, and other things that may be much cheaper in a less urban environment.
Just as an example, an apartment rental tool gives me a range of $600-$1400 to live in Raleigh (our big city). Pulling up a rental map in Chicago gives me a range of $1400-$2800 for a two bedroom apartment. A vet also has to eat that cost difference, unfortunately.
We are as gods to the beasts of the fields. We order the time o' their birth and the time o' their death. Between times, we ha' a duty. - Terry Pratchett.
"Men have forgotten this truth", said the fox, "But you must not forget it. You become responsible, forever, for what you have tamed. - Antoine de Saint-Exupéry