Medical school committees can fill their classes many times over with well qualified applicants. [This is particularly true in the top 2 tiers.] However, what really distinguishes people who ultimately obtain acceptances after interviews is their sincere interest in that school. After you interview several schools, you'll get a feeling for the sense of mood & attitude at each institution.
Ultimately, medical schools want to fill their classes with students who enthusiastically want to be at their medical school. Whether that be for geographical or professional development or both. That further explains why CA is such a competitive state as there are more applicants than any other state, by far, and per capita has fewer positions for medical school.
You may encounter schools that emphasize primary care or other aspects of health care. Most universities though will tend to offer every specialty and residency available. If there's a mutual interest between your own interest and what the school emphasizes - that's the potential for a win/win situation.
I recommend that applicants send their absolute #1 choice a letter stating that & why. This allows you to stand out from the crowd the more genuine your reasons are and adds more depth into your application.