A good example of this was Phil Simms, who lived on the short and intermediary passes. The media always made a big deal about his rating, but it came mostly from safe passes. There's really no comparison to the guys like Bradshaw and Tarkenton who aired it out frequently (and took the corresponding INTs and incompletes).
Owners, coaches, and perhaps even fantasy players focus on the "ideal model" for a quarterback, and praise whoever currently fits the bill. Right now, the big scramblers are in fashion, so McNabb gets called the "prototypical quarterback of the future". If enough people buy into the hype, big scramblers will get precedent in the draft and command greater salaries. If enough of them start for their teams, alot will succeed for various reasons, and the success will be "proof" they are indeed the prototype quarterbacks.
Meanwhile, other types of quarterbacks will continue to be successful, just as they've always have been.