My waitlist is about 3 years, now. I charge what I need to earn to meet my financial obligations, keep an emergency fund and life insurance, take a couple of vacations per year and fund my IRA. It has nothing to do with whom is on the list. I also have no desire to earn more, more money = more problems in my experience.
I love my life as it is.
My tuition rate is fixed, increases yearly (just like my clients' wages) and reflects inflation in my region. I am not sure what you mean by
"vary the pricing based on the number of customers". It has nothing to do with the number of customers, that is a fixed number, too, set by my regulations. I did not choose it and feel it is low for my ability.