One of my moms wanted me to drive her 2 kids to preschool and give them a discount, for the monthly amount of the preschool. More work, more expense on my part (gas money), and less pay. I couldn't accommodate that. Even if I wanted to, I financially can't do it.
I do a preschool inspired program. I have Master's work in Education, and I work on activities with the kids all day long. I teach the kids all day long. We do crafts, math, hands on science, montessori activities, etc.
I do send my daughter to preschool, only because she needs to have experience outside of my home. Also, she is too mentally old for the daycare setting- she has outgrown it, and she tends to wear me out
I can see why a parent would want to pay less, but it is much easier for a provider to just replace that child and have the same amount of money, without the hassle and interruptions of children coming and going. Parents are paying for a spot, and hourly, part time care IS more expensive than full time care, so really they are already getting a discount.