The NCAA and high schools jump right into to it but the NFL can't? And, don't give me the line about how the NCAA schools all schedule cupcakes to open. That just isn't true, look at the schedules.
Once upon a time preseason was a necessity because the NFL was a part time job. That's not the case anymore. They are in shape and know the playbook before camp starts.
The NFL isn't the NCAA. Even the jump from high school to college is nothing compared to the jump from college to pro. These dudes get paid for making plays, and it's a whole different intensity.
As far as preseason: college players that you cite need it more than anyone. To get the speed down, the physicality, the athleticism. The pro game is nothing like college, it's not even close.
Preseason isn't for your 1's or even 2's, it's to figure out what you have coming out of college, in the draft. You see the promise, everyone does. Without it they just ride bench until it's their turn in the rotation.
And I agree that it'll disappear. When that happens you can kiss fundamentals goodbye. Pro coaches fix bad technique from tape. Without preseason tape there's nothing to work with until they've already sucked a couple of real games.