"This far"?
I rarely see professional online testing that is this sophisticated, thorough or accurate. Especially the big publishing house quizzing services. "It marked me wrong for a correct answer" is the number 1 complaint I hear, followed closely by "It's incredibly slow".
So far this collection beats what I have sampled (sapling, mastering ..., OWL.)
I'd be afraid that, if Arduino LLC got involved, it would become a marketing tool, and feature the MKR boards and other hot items, for example.