Has CGC lost it's luster?

First off, don't get me wrong. I appreciate the services that the men and women over at the Certified Guaranty Company do for us. They put comics through a rigorous series of tests to see just what quality it's in. And this benefits people greatly when they buy comics online through services such as eBay. If I see a comic in the CGC slate, then I have the peace of mind to know exactly what I'm getting myself into. The thing that I find most disturbing, however, is that people seem to feel they're entitled to hundreds (if not thousands) more simply for that grading. On comicspriceguide.com a NM copy of Fantastic Four #48 is valued at $1400. A 9.8 rated CGC copy (NM/M) on ebay has an asking price of $9,900 and a 9.4 rated CGC copy (NM) is going for $2500. It's the same book, the same quality (granted, the 9.8 is on the high end of NM) but vastly different price tags. I understand that the prices I see have a human factor attached to them, so they're going to vary from what a price guide will tell me, but this just seems to get into untold levels of ridiculousness. Maybe it's just me.