However, a major hurdle at US universities is FERPA [1]. FERPA (but really the fear of litigation under FERPA) is one reason why universities host their own software.
I fully agree -- people underestimate this issue. We recently had a long discussion among the CS faculty on using GradeScope (a software for grading paper exams). It looks great and I would love to use it, but the feedback was that the University would not approve of it for privacy reasons. Even using Google forms is problematic for that.