You seem to fundamentally misunderstand what the question is. “Grade inflation” doesn’t mean that you get a higher grade going to an elite university than a local public school, or that you got a higher grade in college then you did in high school. That won’t be true for the vast majority of students. Grade inflation means that students at the University of Overly Large Balloons today are getting higher marks for equivalent work to students at the University of Overly Large Baloons in 2000.
See the chart at the top of this page.
I also wanted to address this line:
Yes, there are some schools whose students had an average GPA of 3.8-ish from High school, but then 3.0-ish while exiting. But those grade-deflating schools are extremely rare. I can only come up two names out of my head.
This is not close to true. Virtually every elite university in the US is an example of such a school. Out of every Ivy League school, the University of Chicago, MIT, and I’m sure many more (stopping because I’m bored, but feel free to google “Median GPA UNIVERSITY” for more data points) we see there are TWO universities out of 10 with median high school GPAs below 4.0. In both cases it was 3.9. The vast majority of students at those schools are not graduating with grades similar to what they had in high school.
This isn’t a phenomenon restricted to elite private schools either. 94% of UVA students got a 3.75+, the median at UCLA is 4.39, and the median at Georgia Tech is 4.03.
Even at schools where the median isn’t so high, many students have a very high high school GPA. For example, 25% of UIUC students had a 3.89 or higher.