Earlier quoted context omitted.
Do most people learn well from traditional methods though? If dropping out of a MOOC involved a big financial hit, social humiliation, and the loss of a great deal of personal freedom, the completion rates would skyrocket. Completely different incentives. The reasoning that traditional education is successful because it has high completion rates because of external pressures is a bit circular, isn't it?
Perhaps. The question is which of those things really move the needle; can you have some, not all? For example, our completion rates are 90%+ - better than universities, but there is no social humiliation, loss of personal freedom, or financial hit.
I think all educational outcomes should be measured with respect to the answers to these two questions.
K12 schools in extremely wealthy areas can compare themselves to like peers, but comparing themselves to high-poverty areas is a useless comparison. Neither institution would do well under the other's constraints.
For-profit higher ed is definitely the same way.