Cutting the middleman

So, Builder is still determined to get the Things into a school, any school , no matter their personalities.  However, Small Modox Girls may be out of the running.  (The price tag scared off Builder, and their hard-sell tactics with a side of soft deception scared me off.)  His new project is Big Mainstream Girls, where one of our nieces is enrolled.  (It came highly recommended by my SIL--whose kids go elsewhere.)
My response:  Isn't that particular niece still illiterate--in the third grade?
Builder then said that it's not the school's fault, because the girl has a learning disability and her mother doesn't put in the time I put in.
Of course her mother doesn't put in that kind of time.  The girl goes to school!  The school, which charges tuition, is supposed to handle that.  And, if I have to teach my kids everything anyway, why not just cut the middleman and teach them myself?  (Incidentally, Thing 1 may have a learning disability as well--but she's still reading at least at grade level.)