Well, if the National Guard is only for use stateside, then why is the federal government picking up the tab? If they are primary state use, then the states should pay the whole thing.
Probably true. But the way it is, when they are training, the federal DoD picks up the tab, as it does when they are federalized, such as for overseas deployment. However when they are operating on state orders, they either get paid by the state, or from a different (i.e. FEMA) budget bucket at the federal level.