Garden State was basically Ferris Beuller's Day Off done for millenials. When you say "the high school trope" you're basically talking about "coming of age romances" which are not going to go away. I would argue that Boy's Town was as much a part of "the high school trope" as Breakfast Club and it was long enough ago that Mickey Rooney played a 15-year-old. You want original plots? Go watch Brick. Report back for science.
Yeah, I've seen Brick. Falls into the movies set around high school but not "high school movies" (coming of age romances, sure) category. It seems to me that what's largely replaced the sort of movie you mention is the mid-twenties rom-com, the Adam Sandler/Jennifer Aniston/Ashton Kutcher stuff. My main problem with arguing this is that I watch good movies almost exclusively. So my data set is incomplete.