Well I would agree that if you just worked as a MA behind a counter it would be a wasted degree. But... Like Lara's example, you can use your degree to work in the field of cosmetics is you want to.
I'm sure there is a lot more to companies like MAC, than just the frontline of the company that we see at the counters and pro stores. They have an entire corporate side of their companis as well. Research, design, marketing, advertising, etc etc etc.
While in college, you also dont have to have a, "specialized degree." What I mean by that, is that you dont necessarily have to learn a skill or trade in college to use your degree. Obviously, that's going to depend on the degree you major in. But there are several broad degrees like Business, Communications, Marketing, and others (along with your under graduate course work) that serve to give you a global outlook in the working world.
It's really hard to put a lot of this together when your 18 or younger, but you start to understand the value of a degree (even a broad one) once you get involved with the other 1/2 of the working world. The corporate side, which isn't directly accessible or visible to the public. In retrospect I wish I had finished my business/marketing degree while I had the chance. I wish I had it today not because I want ANYTHING to do with business marketing. But merely for the interview opportunities that having a degree on paper provides.
Your parents aren't lying when they say a degree is a, "key" to a better job. I've lost track of the number of complete IDIOTS I've come across in the working world. Idiots who get paid signifigantly more than I do, not because they know more about how to do something, but because a piece of paper says they do. And being a girl doesn't help. Guys get the benefit of the doubt that they know what they are talking about. Women have to prove that they do (Sadly even to other women). So every little bit helps.
So remember you dont HAVE to go into college knowing what you want to do (I sure didn't, but thought I had too), you have plenty of time to figure that out after you graduate. Not to mention i would bet the vast majority of people didn't start working at their current jobs because it was their dream job. They started working becuase they had bills to pay, and mouths to feed.
So yah just remember. If you KNOW what you want to to, college is GREAT for that. But it's also great even if you dont know what you want to do. Also probably the one thing I forgot to mention. Life after college isn't always what you know, it's WHO you know. And college can be one of your greatest opportunities in life to meet as many people as you can, and to start building a reputation for yourself. And ironically it's great for that too. Join a Sorority (there is more to this than just partys), join tons of campus clubs, get involved with student body, do community service (there are types other than physical labor). Just whats availible through college can serve to give you an amazing resume for the day you graduate. But again, thats only if you want it. You can also do the bare minimum, and get nothing out of it other than a degree you dont know what to do with.
It really is up to you
Hope that helps.