Unfortunately students have the same mentality and have no buying power on their own. Khan Academy has built a great brand but is free. The demographic analysis in the article supports the thesis -- in my unbiased opinion ;-)
Let's talk data. How many students spend money on educational services? 15% of students take SAT or ACT prep outside of school. By the time a student is 16 and has some discretionary spend and has some influence of a parent's spend. If students took their spending power/influence and prioritized educational spend you would have a lot more than 15% of students getting test prep outside of the school.
Consumer spending is huge. Consumer spending on education is large. Consumer spending on education where the primary driver is quality is much smaller.