GM, Parts Availiblity & SPRINT

It seems everytime you look up, yet another part is going on backorder, sometimes indefinatly. I get answerbacks all the time that say "currently this is no vendor", or "undergoing contract negotiations" or "product undergoing testing for quality assurance", or, My VERY Favorite, "vendor is short parts to make kit". You dutifully put in your SPAC case (knowing that you just lost all your discounts, return reserves, ect) and wait..........and wait........and wait. I just don't understand why GM doesn't care about the customers who already bought their product, versus the one who MIGHT buy one. Silverado truck bumpers are a prime example. The last one I ordered took 6 weeks, and that was with a SPAC case, and me calling everyday to give them sprinting dealers names, phone #'s ect. I think the dealers need to find a way to get us our discounts, or at least return reserve BACK on these type parts. (btw, the thing that got me started on this rant? part # 12521285, ordered 11/12/99, Seat Adj for a 1997 Park Ave, SPAC case since 11/23/99, still no date on when I might get one)