Popular misconception: Non profit doesn't mean officers, workers, don't make good money. Colleges are non profit, but top college presidents make over $1million+
Non-profit tax exempt status does, however, require that the organization operates to fulfill a certain purpose. Further, and more importantly for the College Board, a non-profit cannot unreasonably compensate its executives or operate to substantially fulfill a purpose that doesn't qualify for a tax exemption.
The problem with the College Board is that its purpose has veered far more toward paying its employees than education. It doesn't deserve a tax exemption.
And as for rich people wasting their money on prep, let them. It's their money. They have the right to spend it. Especially since prep is ultimately not all that useful or necessary. I got my 36 without prep.
The real problem with this is that the summer test was exclusive to this program, and the deeper problem with the standardized testing system is that wealth provides such a significant advantage.