Techs (for states that require technician certification, it's a two year degree) do a lot of the work with pets. There's often more than one technician per doctor. That reduces costs. Doctors are still needed because, unsurprisingly, cases can have a lot of nuance that requires significant training to see.
I'm sympathetic toward animals, but there's a lot of them that are lucky to have anyone take them in at all, and a lot that aren't that lucky. If someone wants to get an animal some level of care without there being someone with a postgraduate degree to supervise (instead of no care), that sounds like a good thing. They could always be referred to a more qualified vet if needed.
For the routine tasks, eg flea medication or bloodwork, a vet isn't helpful. For difficult tasks like surgery, a vet is too expensive.
I'd rather use a quack in every case.