Depends. Mathematics? Chemistry? There's some room for compression there, but not much. If you ditched all of the absolutely useless "general education"[1] classes, and kept class sizes small enough to allow time for individual coaching, I think most STEM undergraduate degrees could fit nicely within two to three years.

[1] Students are welcome to "expand their horizons" when they aren't paying thousands of dollars for the privilege of being forced to do so.