You could use the exact same argument even for many engineering degrees. A lot of people spend a lot of time, and money (from loans) trying to get CS degrees, only to fail to get through to upper division courses before changing majors. Is that money wasted? Should we move towards a model where your major is preselected for you before you attend college, based on your aptitudes, without you having any say in the matter? After all, we don't want to waste any money. What about if the major was preselected and you still failed to make any progress?