<p>Public schools would not be worried about the loss of revenue from dropouts, since they provide a net subsidy to most students (the in-state ones who have discounted tuition). But from the state government’s point of view, subsidies on students who eventually drop out are mostly wasted compared to subsidies on students who graduate and (on average*) end up contributing more to the economy than a dropout.</p>
<p>*Gates/Jobs/Zuckerberg/etc. are extreme outliers among dropouts – and it is likely that some people who leave college to do similar but unsuccessful startup ventures just go back to school and finish their degrees.</p>