Go back and look at how many teams draft TE's in the top 10. It NEVER happens because the position isn't worth the value of that pick.
Not promoting the idea, but Vernon Davis and Kellen Winslow Jr both went #6 overall, and the Vikes took Kyle Rudolph (Notre Dame) at #11 two years ago. Attitudes change over time. I think the Pats TE dominated offense may be changing the perception of the position, as well as impact players like Gates or Gonzalez over the years.
Never used to see a safety go high, either, but in recent years Eric Berry and Sean Taylor went #5, LaRon Landry went #6 (the year the Jets took Revis at #14)...
The league evolves, so do drafting habits.