When tanks were very similar, M60, M60A1, M60A2, M60A3, etc., the older versions got stored out there. During Jimmy Carter's Administration, the Defense Budget was slashed drastically. Repair parts were backordered for months. Eventually, they went to SIAD and scavenged parts from the older tanks. Many of the vehicles are not broken down heaps. They are just outdated, but still had almost new parts on them when they went into storage.
Then they had to have the latest and greatest M-1 Abrams tank, which is a totally different animal. Nothing from the M60-series can be used to repair an Abrams. Of course, now we have the M1A1 and the M1A2 models, so they can pull parts from the old M1s.
Now imagine if all of your Abrams tanks got destroyed somehow. You bus thousands of tank crews out to the desert, and they are ready for the next battle.
Also note that this arsenal is in California. The nut-jobs out East should pay attention to who they anger.