Well not only in Canada..its the same thing in USA too. People know that in US you can not make your way to the college just by working in a gas station/ delivering Pizza etc. Out of 100% how many graduate?? Managing work/study/finance is a hard job. Only who are determined that is no more than 10% finish their study and the rest is just working and paying the tuiton fee to the college just to maintain their legal status. Look at the people who got DV visa its the same issue..how many DV visa holder got a good job. In canada they give visa through point system here in US they give lottery and invite people to do the job that US people wont do. BUt people know it and they still come here so people dont complain.