this is also because purdy needs a hop step to drop a ball 30 yards downfield (hop step = more time). I am guessing Dekkers release for a 30 yard pass is much faster than Purdy's.Honestly I think the O line was the bigger issue we didn't see more downfield throws.
1) not enough time in the pocket Purdy was safe to look downfield.
2) WR need some time to get open downfield.
I think next year will have improved line play i hope. which should open up more plays downfield. Purdy had a good enough arm for deep balls.