Most commuters don't ride the really expensive bicycles. Commuters tend to be less snobbish than roadies. However, nobody really wants to ride a Walmart bike, if it can be avoided. That's why we all try to maintain jobs and incomes that can one day, afford us the opportunity to upgrade our bikes, or replace them with newer ones, when possible. I guess that's why we commute to work and to school. We do it to maintain and improve upon both our lives and our rides.
Hey! That sorta sounds like you too... College student!
PS.
Actually, if you're good with a wrench, you can MacGuyver a Walmart bike into service, indefinitely...