Room and board is about $13K, or slightly more than 1K/month, which seems pretty reasonable.
Rate-card Tuition is 52K, but they have a 7:1 teacher-student ratio ; If you assume each teacher makes 100K/year (not unreasonable for PhDs), that's about 13K just in teacher salaries ... add benefits, offices, etc, and you're at about twice that, so 26K just for faculty; add some for facilities and management, and their cost is probably about 40K/year per student, so a 20-25% markup, doesn't sound unreasonable (and then almost no student pays the sticker price).
High-quality liberal-arts education is really expensive, but it is because it is very labor intensive (both in students and faculty).
BTW, other universities will do it cheaper by either paying their faculty much less (which usually leads to quality problems), or having much larger classes, or crummy facilities, or government subsidies (or all of the above). Community colleges do an amazing job for the price they charge, but it's not the same education :)