Programs are ultra competitive. Sure there are some exceptional students who can work part time and go to school full time but there aren’t that many of them. For the majority classes/entrance exams are all they can handle. I had a number of friends who worked side jobs and tried to get the grades needed to get into school fail. They were smart kids and most likely could have done it at other state universities but BYU will chew you up if you are not an elite student. I would not have got a partial scholarship at BYU or been admitted to Dental school if I had to work a part time job during the semester.