I also have been using a multi-vet practice in the last 2 towns I’ve lived in. There are the conveniences that have been mentioned, plus a vet has others to call out to for another opinion at any time. The largest practice I worked with had specialists so that you knew you were getting one the best lameness vets, or neuro vets, and so on. Single-vet practices also help each other out this way, but all in one practice seems to allow that more quickly and efficiently.
In your place I would probably start asking around as to why the high turnover. As you point out, it doesn’t help the continuity of care, and it could indicate problems in the practice that can affect the care. Vets leaving after 5+ years wouldn’t concern me, but vets leaving after 2 years or less on a regular basis would definitely concern me. A constant roster of new names without the old names would concern me.
Are the new vets mostly fresh out of school or mid-career? Sometimes a practice in a less-populated, less busy area will be a place where new vets start their career, but also want to move on from for a busier, broader-scope and more lucrative practice.
Is this a common issue among other practices in the area? How about small animal practices? That would indicate that it is a geographic area that is not lucrative enough for most vets. Doesn’t fulfill their ambitions.
Management issues could be interpersonal, or they could also be quality of care issues that the vet staff don’t care for. Lack of resources; or perhaps pressure to make what the vet considers a sub-optimal decisions (high emphasis on surgeries, or discouraging surgeries, for instance). It could also be that the vets feel they can earn more elsewhere, which will make turnover constant. And if that is the case I’d be more concerned about a vet who stayed. Maybe they love the area, but maybe they can’t get hired anywhere else.
Ask around and try to snoop out opinions of those in the know if there are any concerns over the quality of care in the practice. Are they known for making mistakes in diagnosis and/or treatment, for instance.
I’d probably look for a more stable practice, even if it was a little farther away. But if you are in a smaller-population area it could be that this is just the way it is in most vet practices in that area.