A lot of basic research is also done in animals, it's a pretty important part of the process that led to many drugs being tested in the first place.

But it's true an understanding of the animal is usually treated as an unimportant tangent. Like you might introduce a mutation into a mouse gene that is analogous to a mutation thought to be relevant in humans and then look at how that affects some other biomarker of interest in the mouse. But you're not going to be studying some issue that arises naturally in mice. Hell you're only using the mouse because it's an established lab model, you don't give a shit about mice.

Also, all the mice are hella inbred and grow up in a sterile cage, so they're hardly even reflective of IRL mice. So even if someone did want to fund lots of research on mouse veterinary science, it would still be a long road (technically and culturally) to get that integrated with basic medical research.

I'm not saying this is the way it should be, but it's the way it is.