The more or less consensus best WR currently playing is Antonio Brown. I believe he was a 6th rounder.
Kupp a 3rd rounder mainly because he was from a smaller school and he doesn't have blazing speed.
Not that the guys that went before Kupp are chumps; but the value is about as good as it gets.
Brains, character, attention to detail, work ethic are every bit as important as height, speed, weight.
Fans, especially, seem to think (for instance) that RBs need to be 4.5 guys, WRs and CBs 4.4 guys, TEs 4.6 guys, etc. Yet when you see the Combine performances of some the top players at their positions, you find some of the best RBs are 4. 6 - 4. 8 guys, WRs and CBs 4. 5 to 4.65, and TEs as slow as 4. 85.
Plus, I think that quickness in today's game might be more important than long speed for skill players.