I bet you're right that a lot of parents aren't all that interested in the quality of education their children get, as such. But ...
If you say your school offers world-class education, parents have no reliable way of telling whether that's true. If it isn't true and they send their child to your school, they still have no reliable way of telling; in particular, they will have a lot of trouble convincing a court that your description of the school was dishonest.
On the other hand, if you say your school has free laptops, no homework, lots of high-tech gadgets, and free trips to Spain, parents can check that pretty easily and get you into legal trouble if it isn't true but you said it was.
If parents care more about things they can actually check, that doesn't necessarily mean they aren't interested in education. They may just be realistic about what they can trust educators to do.
It isn't so much that parents aren't interested in the quality of the eduction, as much as the annoying fact that teenagers have wills of their own. You make it sound like the parents are the target customers for these schools, but based on how the schools target their advertising they realize that their target customers are very much the kids.
Now admittedly I don't have teenage kids, but from what I hear I imagine it is non-trivial to tell them that they can't go to the school they have their heart set on and instead must go to a school they don't want to go to at all. And even if the parent does win that particular battle of wills, I image that the kids motivation will have taken quite a beating. I suppose at the end of the day most parents reason that it's better to send their kids to a bad school they are enthusiastic about rather than a good school they don't want to go to.
If you say your school offers world-class education, parents have no reliable way of telling whether that's true. If it isn't true and they send their child to your school, they still have no reliable way of telling; in particular, they will have a lot of trouble convincing a court that your description of the school was dishonest.
On the other hand, if you say your school has free laptops, no homework, lots of high-tech gadgets, and free trips to Spain, parents can check that pretty easily and get you into legal trouble if it isn't true but you said it was.
If parents care more about things they can actually check, that doesn't necessarily mean they aren't interested in education. They may just be realistic about what they can trust educators to do.