Peter, and others who have mentioned market competition, I agree with you that staying competitive is an important reason--balancing competitive edge with best practices is also important. Four-year institutions have discovered that they are "cannibalizing" some of their on-ground student enrollments. I'm not sure if enough research has been done to prove the significance of that--perhaps it allows traditional students the opportunity to a) take more courses, especially if two required courses are offered at the same time, or b) progress toward graduation more quickly.