I bet if you made your BOS trial and sold it to the top schools in the state to use as their trial then you would have people getting over 70%. You just haven't got enough of the population doing 4u doing your exam every year (because you are only going through BOS). It's not a reliable experiment, meaning its not valid either.
That would be true, if all of the applicants were people who happen to be roaming around the forums.
However, how it generally works is that I link it to a student, they send it to their friends who go to 'top schools', then it snowballs and spreads from there.
For example, I have at least five students from each of the top selective schools attending this year. In fact, there are also more than 20 students from a particular top selective school who have registered.
However, I agree with your sentiment that every year there will exist some students who CAN do well in it, but for one reason or another they are not sitting the paper. There are some very bright ones out there, and not necessarily from selective schools either!
