There are a lot of successful quarterbacks out there, but that doesn't mean they all have sound mechanics. One of the first things I do when I get a quarterback who has had success is figure out if he's successful due to his good mechanics, or successful in spite of bad mechanics.
There are obvious examples in the NFL. Johnny Manziel has been a hot name the last few years, but many projected his success wouldn't translate to the NFL, in part because of his mentality, but also in part because his fundamentals simply didn't show a quarterback who could be consistently accurate or efficient. He had a great deal of success at Texas A&M, but that was in spite of poor footwork, bad reads, and scattered throwing mechanics.
On the other hand, you find quarterbacks like Andrew Luck, who has impeccable mechanics. He throws from a solid base whenever he can, he matches his footwork to his reads, is able to throw in rhythm and deeper into progressions, and has solid throwing mechanics. Yes, it is important to be able to be effective when the play breaks down, which is one of Manziel's strengths, and Luck also does that well.
On the high school level, some quarterbacks are still so much more athletic and gifted than their teammates and opponents that they are still able to be effective, despite poor fundamentals. They end up on the Johnny Manziel route to success. If that is coupled with a poor attitude, ego, or arrogance, they can be some of the hardest players to coach. It's difficult to tell a kid who throws 20 touchdowns and only a few interceptions on a winning team that he's doing things wrong, or that his footwork needs to be corrected, or that his throwing motion needs to be tweaked. The player who won't listen to coaching is setting himself up for a fall - he's doing well playing against lesser competition and getting away with fixable mistakes, and is choosing to ignore advice. When the competition catches up with him at higher levels, he won't be able to take the coaching to improve and won't be gifted enough to succeed on talent alone. That's a dangerous combination.
Fortunately, I have found this player to be in the minority. Most every quarterback I have worked with has been willing to take coaching, regardless of previous success (or lack thereof). A strong combination of humility and hunger for improvement make for the most coachable players, and therefore they make the biggest strides.
The example I use with the kids about success as relates to mechanics comes from basketball. If a player shoots granny-style, from between his legs, and he can make 6/10 shots that way, does that mean he is doing it right? And, if when he tries to shoot with proper form he makes only 4/10, does that mean he should revert back to his old shot?
Obviously the answer I'm looking for is no, he should continue to work on doing things the right way, because at some point poor technique is going to catch up with him. Shooting granny style is limited his potential, and taking a step back and learning the correct way will lead to him taking multiple steps forwards in due time. We call this process over product. When we focus on the process, on doing things the right way, we make more improvement in the long run than focusing on the product, or in this case how many shots go in. And, in nearly every case, when you work on the process, the product will take care of itself.
So the end point of this post is try not to tie your ability only to results. Look at mechanics and fundamentals objectively, and seek out ways to improve and do things better. It might be harder at first, but in the long run your hard work on the process will pay off.
Quarterback Coach Alex Drayson will put up articles, thoughts, and reviews to help you stimulate your journey towards being the best QB you can be