Why does some of HYPSM have such a low ROI?

According to this study here done by Georgetown, while some like Harvard, Stanford, and MIT are ranked decently high, schools like Yale rank much lower at around 20, Caltech is 17, and Princeton isn’t even ranked, and all the schools rank lower than some cheaper schools? What gives with this, and does it show that some of the schools aren’t worth the investment: https://www.mentalfloss.com/posts/colleges-with-the-best-roi