Is it my fault I'll be here 5 years?

These days if you graduate in four years, you're outside of the norm! Personally, I've taken full loads every semester but won't be able to get out in 4. I have 15 hours left, but one of the remaining classes is only offered once a year however, which happens to be in the spring. I couldn't get into that class due to a prerequisite forcing me to stay another semester. Nobody caught this problem early enough, and now there is nothing I can do about it. I hated telling my parents what happened, since it all boiled down to having an extra semester's worth of tuition to pay. My plan is to work nearly full time next year at the engineering firm I'm employed with now, and split my hours evenly through both semesters. This well help a lot with the bills of an extra semester and has turned my situation into something not all that bad. But I hear about this kind of thing all the time, and feel for the students who don't have a backup plan with what to during this added semester. Who is responsible for this? Should it be the advisors job to catch these mistakes before they happen? I realize responsibility should be taken upon by the student, and do not blame anyone but myself for my situation. However detailed information about every class that is required to refrain from this occurrence can be hard to find. What can be done, if anything, to keep this from happening to students in the future?