The Market Failure in K-12 Education

The primary market failure I see in K-12 education is that poor minors needing tuition money are not allowed to enter into long-term contracts that surrender a fraction of the alleged increase in earnings that a tuition investment would buy them. If education investments are as wise as we liberals claim, then such contracts should be able to make education for the poor self-financing. In the absence of such contracts, I don't mind the geolibertarian citizen's dividend financing tuition vouchers (or land value tax credits for tuition donations to) for poor families. There is no more need for the government to own and operate schools than to own and operate grocery stores.