The catch is that universities must spend on impressive new facilities, buildings, housing, and sports if they want to remain attractive to their customers (students). Most universities are still competing for students. Many students survey a lot of universities and do campus tours to determine where they want to attend. The short campus tours don't really show them anything about the education they receive, but the…
However, very few colleges want to be the university that produces an adequate education with extremely low cost. They all want to be the most prestigious University, costs be damned.
If you want to get a sense of the differences, community colleges are focused on students, not prestige. Community college costs is California are $550 per semester, while UCs are in the $13-14k/yr ballpark.
Undergraduate lecturers can actually be better at a community college IMHO, because they are career teachers, not career researchers.