OK, more like 20 years. The last time we had a WR ranked in the top 10 in DYAR was when Irving Fryar was ranked 7th in the league in 1994 (Marino). Crabtree was ranked 6th in 2012 (Kaepernick/Smith). Marshall was ranked 18th in 2011 (Moore/Henne). I'll grant you, the top DYAR ranked players typically have elite QBs throwing them the ball, for instance this season if you convert the top ten recievers name to their respective QB you would have:
1. Roethlisberger
2. Rodgers
3. P. Manning
4. Rodgers
5. Romo
6. E. Manning
7. Ryan
8. P. Manning
9. Washington's revolving door of QBs
10. Flacco
For me I would look at that and instantly recognize Jackson could very well be the top receiver in the NFL considering the guys throwing him the ball. And I wouldn't put Eli in the same category as Rodgers so Odell Beckham should be elevated as well. So as far as Crabtree is concerned you can only come to two conclusions: either Kaepernick is much better than he gets credit for and is elevating above average receivers, or Crabtree was even better than his ranking of 6th in the NFL.