Yes, the truth is that very few places are actually "selective."
Most universities will take an available warm body at some fairly low dollar amount, because the marginal cost of one additional student is actually very low. If I'm Bama, I can almost always take one more student without hiring any additional faculty members, building any new classroom space or any new dorm space, so what does that kid cost me? Almost nothing, so sure, I'll take the five grand. You say, sure, but if I take 100 more, I do need more space and faculty. True, but the math still works that the marginal cost is quite low, and a warm body paying a little is better than an empty seat. Same principle, in some sense, as Priceline. The hotel would rather rent the $150 room for $50 than take nothing, because the maids are already coming in, the heat is already running, etc.