In 2006, Jonny Harline by himself had 935 yards on 58 receptions and 12 TDs. Dennis Pitta had more receptions than Collie in '07 (but 100 less yards, still he had over 800).
So Arod's offense just flat out utilizes the TE less than we are historically used to or he isn't teaching the QBs to utilize them. Which is kind of a shame and frustrating to us as fans since the TE has historically (and currently) been a strong position for us.