Excellent point and it's been this way as long as I can remember. The media always gives the benefit of the doubt and overrate anybody who has a strong arm, quick release, or can run the ball. The guys that consistently go out there and win, show mettle in tough situations, and aren't "exciting" have to prove themselves by winning a Super Bowl first, then they'll get the love and respect from the media (like Montana and Brady).
The scary thing is there are some guys in NFL personnel departments that use the same type of thinking. How many teams gave Jeff George a shot simply because he had the all-world arm that everyone thought deserved being the first overall pick?
As far as Tua and Purdy are concerned, I don't see why most on here are promoting Tua as one of the best in the league, but not doing the same for Purdy. They have many of the same traits and physical attributes. They run the same offense and have similar stats. Frankly, I don't see how they're both not top 5 this season.