What you posted is in line with current .edu thinking. If you were trying to learn something serious would you prefer a 15.6” laptop display or a 13” Neo display? Same weight. 15.6” LG Gram laptop weighs same LG Gram as Neo.
No I am telling you what the university recommendations are, and what are in use on university campuses. Only folks doing things like heavy video or engineering work are lugging 15 and bigger laptops.
Note taking, web browsing, email, paper writing, media consumption etc, are the standard use cases, and they are not coming to college generally with 15+ laptops.
You want to try to change the market go right ahead, but that is the market, and this laptop is going to eat most of the low end machines lunches in this space.
Chrome Books are pretty much the same, yes they make 15 and 17” chrome books, they do exist, but not likely to see a single student in any school district carrying anything larger than a 14” at most.
So, kids who have been using 13/14” machines for the decade before they went to college for their schooling needs aren’t chomping to say I need a larger screen.