History has shown that most QB's fail regardless of height. The only thing history has truly shown in regard to short QBs is that they don't get nearly as many opportunities to be NFL starters (or even college starters) as taller QBs do. Shorter QBs don't bust at any higher of a rate than taller QBs. What matters the most when determining whether a QB has success or not is if they can read the defense, get the ball out on time, have the arm talent to get the ball into tight windows and stay healthy. Almost every QB bust in NFL history failed because they couldn't do one or more of those things and you never can know for sure if a QB will succeed at all of those things until you see it on the field in real games.
Sure, but if you break it into segments of success, it's a bell curve. Shorter guys struggle to show NFL success, really tall guys struggle to show NFL success. There's readily available information on this.
The huge issue I have with your argument about how short guys "don't get a chance" in the NFL is that I've provided lists of short guys who have failed, but no one seems to have a list of college players who weren't given enough of a chance in the NFL, or high school guys who weren't given a shot.
With the desperation for even adequate QB play, I don't think this is an issue of poor short guys just not being given a chance... if you have the arm strength, mind, etc., you're going to get a chance. And if you're amazing, you're going to beat out the guys around you.
I mean, feel free to share evidence of short guys that aren't getting enough of a chance, but this seems like it's just something that some of you feel is happening, not anything concrete with examples of where some kid was clearly amazing but just wasn't picked/offered a scholarship.