I think another factor is the length of time they were in service... Nearly 20 years in some cases. Depending on where it came from, like out east for example, they were already having serious rust issues prior to disposal. Many are out there, but some are downright ugly.
The spare parts availability issue is something I think has really been downplayed. I hear some guys talk like there are scads and scads of Iltis bits floating around. Maybe this is true, but with the cannibalization authority in effect long before they went out of the system, I have my doubts as to how huge the spare parts supply really is. Sure, there are huge quantities of some things available, but its usually the stuff you wouldn't worry about anyway. Personally, if it were me, i'd be stockpiling the consumables now while the gettin is good. With decent running examples of the Iltis already demanding stratospheric prices ($5K seems to be the norm now for an Iltis, and yet I managed to get almost 3 MUTTs for that price with a bit of hunting), i'd imagine spare parts prices will climb accordingly. I'm sure Rob Love could educate the Iltis Folks on what exactly is known to croak and the list isn't exactly short.
Not to go pimping my M151A2 again
, but that is the one nice thing about a having a vehicle that the fleet was demilled and only a few dozen are actually still alive. There is literally a mountain of spare parts floating around that will surely outlast the worlds oil supply.