I think you, like many have a naive view of rankings and prestige as I used to. Prestige differences beyond a certain point is more a function of history and marketing than actual differences in academic quality. Also, by your top 20 allusion, you suggest that schools such as G-town, USC, UCLA, Emory, Michigand, CMU(just outside of top 20 or were in it) are for some reason substantially different or a step down being outside the top 20. The reality is that many schools are similar academically and it is money, resources, and non-academic offerings that make them stand out as attractive. For example, I’ve seen STEM materials from places like Michigan (not in top 20 yet) and they are often a bit more rigorous than many top 20 counterparts, especially in math and physical sciences. Let us also not talk honors courses at a strong school versus regular ones at a “top 20”…I think typically honors is preferable unless your at the truly special ones in the 20 that are maybe smaller than other.