Also, don’t forget that many graduates are not singularly driven by purchasing power in their first job. Many, especially CS/Engineering, are seeking the best opportunities from a technology perspective. They look for companies where they can continue to work on the leading edge of development. Many such opportunities just happen to be in high COL areas. Coincidence? Probably not.
CNBC put a clickbait spin on their article title about the Georgetown Center for Education and the Workforce study. https://www.cnbc.com/amp/2019/12/05/the-top-10-college-majors-american-students-regret-the-most.html
and the wa po wrote an article about it a few weeks ago. The title was not as “clickbait-y” https://www.washingtonpost.com/education/2019/11/14/is-college-worth-it-georgetown-study-measures-return-investment-with-some-surprising-results/?arc404=true