See here's where I mess everything up because this isn't a Black/White, Wrong/Right discussion. I believe you are right about the team invested in WRs. I believe you are right about Coopers contract. I believe you are right in Lamb being a luxury pick, to an extent. I believe you are right that it is not a recipe for success, to an extent.
I don't believe anyone was anywhere near as close, in value, to Lamb at 17.
I don't believe Dallas could afford to not pay Cooper.
I don't think it's as easy to say this isn't a recipe for success when, with what we are working with, we have the statistics to prove Dallas was wrong with drafting Lamb.
Our argument is, and I'm assuming, that Lamb should not have been the pick at 17 because of the defensive needs. We can't shoehorn Dallas' draft picks into a right/wrong situation based off of their failure to hit off of last busts, or soon to be busts, on the defensive side of the ball.