<p>“If you’re right about this, then plenty of people for whom there may not even be an enjoyable math/science EC to realistically do may be completely ignored by Caltech!”</p>
<p>You’re absolutely right, these students are often ignored. If you put two students side by side and they both have fantastic essays and scores, and one has demonstrated better/more clearly their passion for math and science through their extracurriculars, that one will have a significant advantage. This is unfortunately the nature of applications–all colleges have to judge you on is the application, and if one application is weaker than another it is probably going to be less likely to assure admission. Furthermore, since Caltech has a ton of people applying every year with not only good scores and good essays but also strong demonstrated passion, it can generally select the people it views to be the best fit.</p>
<p>Interviews are a great idea in theory, but rarely work well in practice. I have spoken to interviewers for Rice and MIT and they have both said this.</p>