That is said a lot but I'm not sure it's really true. Suh's national prominence really took off his senior year (2009). By that time the recruiting for the Class of 2010 was on the downhill finish. In 2011, we got four-star Todd Peat, he just didn't work out. In 2012 we got four-star Greg McMullen (solid but not spectacular), Vincent Valentine (NFL), and Avery Moss (NFL). In 2013 we got Randy Gregory (not quite the same position but still DL) and Maliek Collins (NFL).
So in the three classes after Suh we got four NFL guys and two more four-stars. That seems like pretty good success.
I think when people say that they are basically saying we didn't get another Suh. But that's a pretty unrealistic expectation.