Disagree on two main things.
Teams do not put more talent on the offensive side. Defense involves reactionary positions that require more talent.
Wide receivers don't beat corners because they're better athletes or more talented. Covering someone is difficult (especially in man with your back turned to the quarterback and ball) because the receiver knows where he's going and the defender doesn't.
As a side note, the vertical route is perhaps the easiest route to defend in man coverage. The quarterback has to throw the ball farther and accuracy suffers. And the defensive back doesn't have to worry about changing directions. Physically the defender may have a disadvantage due to height, but that's the trade-off. You need a small shifty guy capable of recovering, thus you sacrifice height and size.