It's not as if he had to try hard in the first place during his "glory" years at Stanford. Two eight+ win seasons in a badly weakened Pac 10 didn't exactly take that much effort. Pete Carroll didn't have his mercenaries, er, players, quite in place just yet.
To put it this way, arguably, his best season that resulted in a major bowl was 1999, when he took Stanford to the Rose Bowl. He did that with an 8-3 record, and that wasn't exactly very impressive. Seeing Ron Dayne bowl over them in the 2nd half and seeing how they were completely deflated pretty much summarized how those teams must have felt.
Once he got here, he was absolutely lazy when it came to recruiting. He was lucky to get the class of 2003 that was arguably a very good class, thanks to the hype from the 2002 season where almost every break went our way.
After that? He sat on his rear and didn't even reach out to many a blue chip recruit who wanted to come here. Instead, he was happy to passively let two star players the likes of Tregg Duerson come to the program. Looking at that God-awful class of 2004, there were maybe six players in that class that contributed meaningful minutes. Off the top of my head, I can only remember three who were notable.
Darius Walker - One of the better running backs we've had here. He could do it all, and put in a good season in 2004, along with very fine seasons in 2005 and 2006. I don't blame his leaving early, since playing behind that depleted offensive line of 2007 would have gotten him brutally hurt.
Maurice Crum Jr - Not as talented as his father, but still a very solid player for us. Hard working guy, and a better man than his father.
Terrail Lambert - Had a couple of decent games, especially against Michigan State in 2006, but aside from that, not very good.
The mathematics are pretty simple. If you don't have at least 8 players in a class who played reasonable amounts of meaningful minutes, then your recruiting pretty much stank.