Supply vs. Demand it is that simple. The more people buy, the higher the price will go.
When I first started my truck hunt a few months back I walked into the GM dealer and was chatting with a salesman that my girlfriends dad has known for quite a few years and the way he spoke about it made perfect sense.
5 years ago if you would have went into the GM dealer this long after the new models were released you would have seen 8, 9 maybe even 10k in saving and insentives on trucks already booked at 30-35k. Fast forward to now and your seeing what? $7-8k? on the same trucks based at $48-52k and people are still buying. Aside from the low sales numbers that GM has been releasing they are certainly still selling an absurd number of vehicles, and believe it or not, there are still people who go to a dealer, pay msrp out the door without a hassle, and go on their way. Its crazy, but as long as that continues prices will continue to rise.
He even went as far as to say that by the time GM does their next full generation make over you may see those base model trucks selling at that $45-48k target price which bumps your high end trucks even higher than they are now. I reailze that is a lot to speculate but in reality it is certainly a possibility.
I was also not in the market for a $45,000 + vehicle so I held out for one with a $39k sticker price + incentives. If you really shop around, not just local sales lots but really put some effort into finding a deal you can make out pretty good right now. I managed to get the 4x4, black interior, double cab, with bedliner and mudflaps out the door for $34,000.