At this point in his career, I'm not ready to say that Matthews can't do that. And I'm certainly not ready to say that Zay can't.
I feel like the "terrible" trade crowd is arguing with themselves in this thread. Keep throwing out stats about how great Sammy is. Great. I agree, as do most people with two eyes.
The real question is about team building. I don't think it's crazy not to think that paying an elite #1 receiver big money, if he would even sign beyond the franchise tag, is the best idea for a team in our situation. Save the cap space, and accumulate picks, and give us the flexibility to go after what really matter- a franchise QB. Yes, you can try to do both, but the having more picks and more cap space just increases your odds. Plus, you can't pay everyone.
Lets go over the best receivers in the game, again-
OBJ
Julio
Brown
Green
Hopkins
Dez
How many championships? You can do this exercise with greats going back to Megatron, Moss, and TO. Elite WR's are great to have, and yes, good players are better to have than bad players, but great receivers alone just don't move the needle that much. Especially when you have to decide how to spend your limited resources. And double especially on a run first team without an established franchise QB employing a WCO horizontal attack.