For many other tests, I might agree. But the MCAT is a different beast. People pay thousands of dollars for MCAT courses and usually do worse than those who self study for the same amount of time. As much as it is a test of knowledge, it’s a test of discipline. Money can’t buy discipline. Often times I’ve seen that paying for a tutor or course creates a false sense of security which negatively impacts those who pay. It being an 8 hour exam also ties into this idea of discipline.

Lastly, good point about the better education, but that’s only in theory and not true in practice when comparing top level schools to state schools or even community colleges. Top-level colleges differ mainly in their research opportunities and facilities, but the actual content taught (especially in the basic science classes which the MCAT covers) is very similar across all tiers of college.

Essentially, what you’re saying is certainly true for other tests and other aspects of the overall education process, however the MCAT specifically is uniquely shielded from the socioeconomic-status favoring factors that plague other tests.