I can see by your post count that you are fairly new here.
If you research this site, you will find hundreds of threads on that topic.
There is no low census of nursing students or nursing school positions. There is a low availability of places for them. In my program, there were around 500 applicants, reasonably qualified and only 60 positions available. This means only the best are going to get in.
Nursing classes are quite expensive to run, nursing labs terribly expensive to stock, and very few nursing instructors make as much teaching as they can as a staff nurse. Nursing requires much personal one on one attention. Labs require many of the same supplies as medical students, but unless your fees are jacked up to med school level, the school will not be able to get as many supplies. Yet nurses cannot graduate and earn as much as MDs, so to pay high fees. Medical attendings get preferred schedules, time off for research, few overnight calls and many benes to teach. Nursing instructors, on the other hand, must teach 6-12 hours, do 8-16 hours of clinical on site, prep for clinical the night before for 4-6 hours, hold office hours 6 or more hours a day, teach labs 2-6 hours a week. This does not include research, publishing papers, preparing class material or grading papers. And yet they will be paid less than what a 3-12 hour shifts.
In addition, teachers do clinical for 6-12 student groups, with each student taking at least two patients that the instructor assigns, as well as she needs to set up precepting nurses. That means that they study 12-24 charts for each clinical group. And you have to a good, large patient population in a hospital that agrees to host you. Those are in limited supply. A hospital cannot have excess students on the floor, as they will have a poor experience, the staff will go nuts (it is harder to supervise a student than do the work yourself ). Too many "teaching" experiences leaves some nurses at their wits end.
In addition liability insurance for the school is an issue, whether the students have malpractice insurance
, the school generally needs some coverage.
Nursing is not accounting...you cannot add 20 seats to a lecture hall and automatically graduate 20 more CPAs. Nursing requires more than that.