Lisa is a self-employed dance instructor. She has tried to modestly raise her lesson rates three times over the past five years, most recently about two years ago. However, every time she did so, she was forced to lower the increased rates back to their original levels, due to the fact that each time she lost enough students to make the rate increase unprofitable. Although Lisa would like to raise her rates and earn more money, at the moment she has resigned herself to staying with her current rates, in order to avoid the process of losing students and having to rebuild her client base once again.
What assumption underlies Lisa's conclusion that she should not try to raise her lesson rates again at the present moment?