It becomes a cycle: schools take students who have lower grades and scores compared with those admitted to the T10 schools, those students as a group, score lower on Step 1 than students who had, on average, much higher MCAT scores, residencies select based on Step scores and so the cycle continues. With Step 1 going pass/fail, we may break that cycle. However, I do not believe that pedigree alone will be used as a proxy for good Step scores.
Do keep in mind that your performance as an individual is a much more powerful predictor of where you'll go next than the average performance of your peer group. We see this all the time when we get applications from students who attended unranked state schools as a way to save money despite having admission offers at more prestigious private schools.
Also keep in mind that some schools are selecting applicants who want to go into primary care/rural medicine and they consider it a huge success to have 80-90% of the class match in family medicine, pediatrics or a similar primary care residency. So, if a list does not look "competitive" it may be the selection bias of the school's admissions committee that has a preference for applicants who want to be primary care providers.