Have you ever seriously considered PhD programs? No one that I've ever heard of has ever had to pay tuition to attend college for their PhD (myself included). It is usually a "work exchange for education"; a research or teaching assistantship while taking classes and writing a dissertation.

And to say that the learner does not get to decide what they will research for their dissertation is just flat-out wrong. It is assumed that the student will pick what to write their dissertation on - they need to study it in-depth for 2-4 years and picking something that they do not find interesting will most likely lead to dissatisfaction (but it is still a choice).

Granted, a PhD program requires a prerequisite BS degree or equivalent which is generally not paid for and follows a typical regime. However, not all knowledge is the same - highly specialized "brink of human understanding" type learning is paid, unstructured and definitely has no exercises to complete (since the one learning them has the most understanding of the topic).