Most US students don't go to selective private universities that charge $80,000 a year (and most students at those universities don't pay $80,000 a year). Only about a quarter of students go to private universities and most of those are not particularly selective. Most students go to state schools that are a lot cheaper and where tuition is subject to different economic forces.

You can't decide that official inflation figures are inaccurate based on a specific, outlier example, when the official figures are based on averages.

Also, the list prices for tuition and what the average student actually pays out of pocket in the end can be two very different figures after grants and scholarships come into play.

And yes, absolutely, $80k a year in tuition is a massive outlier. Average in-state university tuition is closer to $12k-13k/yr, before grants and scholarships. The extreme majority of US undergraduates aren't shelling out $80k/yr for tuition payments.