The war you pack up to go to might not be the war you end up fighting. All those units that have been converted into provisional MP and motorized rifle companies might need their tanks and howitzers and Stingers if the present war expands into Syria and/or Iran.
20 years ago First Tank kept each tank's basic load of main gun ammo in the racks on the tanks, all the time. We parked them in the Motor Pool loaded, we went to the field loaded, and we went to gunnery loaded and had to download the service ammo onto tarps, upload the training ammo, and when we got done for the day we had to upload service ammo again and do it all over the next day. The point being we never knew when the war might start so we minimized the amount of time it would take us to be ready for it.
I really wish these units were taking everything they need to perform their primary mission. A bunch of people will have to be retrained when they get back if they go a year without doing or training to do their MOS job.