Right, if you're at the level where you could afford the fanciest credentials, you don't actually need them. Then if you're upper middle class (so you don't have unlimited money, but they don't need the credentials), you need to ask why you'd send your kids to college at all. If you've raised an Ivy-calibre kid, presumably they can self-teach with the infinite resources available, so it's not about education.

So the obvious reason for a decently well off family to send their kids to university is because it is far and away the best way to find the person they will marry. Casual dating squanders that opportunity (and promiscuity is linked to higher divorce rates if they do eventually find someone), and they'll never have that chance again. No different from giving your kid a trust to live on and watching them spend it on drugs and partying.

If you're economically secure, immersion in a culture that normalizes positive values is the most important thing you can buy. In fact from that perspective, the hyper-competitive and ambitious culture (to the detriment of e.g. a fulfilling family life) of the Ivys is likely undesirable.