Deploying a Guard unit has a much larger emotional impact on a community then deploying a regular military unit. I think there was a cold political calculation made that that would suit the Boomers ideological outlook just fine. Plus it is a marvelous engine for pork barrel spending since you can hide building a new armory or refurbishing the Guards HQ as “Defense” spending.
Also, re the reduction of our armed forces, Clinton/Gore bragged about “reducing the size of the government by x %.” The reductions in manpower were virtually all military. I guess National Guard units became state funded entities, instead of federally funded.