Lack of intellectual engagement is easy to understand if the first semester freshman student has only one honors class per semester–although your post is a bit confusing regarding “despite the classes being reserved for the very top students in their major”.
And, of course, schools like the University of Chicago, Amherst, Williams, Swarthmore, Northwestern, the Ivies, Stanford, Duke, Notre Dame, Georgetown, WashUStL, etc. are going to provide a much more intellectual environment.
Agree that the honors student needs to look at upper level course offerings at current school versus what is offered at any target transfer school.