It hasn't been too long since I was starting college. For freshman (in the US at least), colleges encourage students to try lots of classes and take their time picking a major. Many schools don't require students to declare a track until they are in their sophomore year -- halfway through a four-year program! Many can be completed in 2-3 years (even "hard" majors, like physics), and the schools design the degree programs with this buffer so students can wait to make a decision. Of course, the schools don't mind recieving four years of tuition for an education that could be completed in three.

But it's easy to blame the schools. In my experience, students don't really make career choices (like picking a major) by weighing the economic costs and benefits. Our current culture in college encourages students to take on massive amounts of debt regardless of their field. For many liberal arts degrees, this is probably a foolish financial decision. But for many college freshman, the apparent difficulty of a subject is considered thoroughly, while the job prospects of a career path are a secondary consideration.