Florida just increased its voucher program to pay for students who want to escape the public schools. That program is now under a ferocious attack by left wingers and the public schools. They will cite some school that has under-performed or defrauded the voucher system and tar the lot with accusations. No where do they mention that the voucher schools produce much better results than the public schools.
I have personally witnessed the effects of bussing. Bad students with attitudes NEVER pick up better study habits from good students. What happens is that the good students pick up smarting off to the teacher, not doing homework, disrupting the class, cutting class, and all the other behaviors guaranteed to produce failing results from the ghetto incomers. Even if the student you mention make it to the voucher schools, the voucher schools usually have the option of tossing disruptive or poor students right out the back door, back to public schools. Thus, the "better results" of which you speak come about from cherry picking.