The 3.0 yards is from this year, which puts him in a group that includes Beckham, JuJu Smith Schuster, Robert Woods. As an internal team reference, Robert Foster is at 2.7.
Maybe he wasn't quite in synch yet with Foles but we know from this forum, that fans complain as a hobby.
Hard to say for contract $$ or when he'll start to fall off, but Steve Smith was effective when he was in his mid-30's.
Tate has hardly ever been injured enough to make him sit, so he might be healthy for a few more years.
I just think it would be good to have a guy on a young team that doesn't need to be 'coached up' -- or-- kicked in the ass to work hard.