What you didn't mention is that the US National Guard is mostly consisted of ex-service members (veterans), so they already have military training. They are not new soldiers. They are also different than reserves, which are also veterans, but have less frequent trainings than the National Guard. In some areas such as air defense, it is actually the Air National Guard that takes the lead, not the US Air Force (which focus on global development, outside the US). This is why they have all the same fighters as the USAF, F-22, F-35, F-15, F-16, etc.