the fact that their growth spurt didn't quite pan out the way they hoped and their athletic skills get passed up by guys that did nothing as a kid. Seems likely here.
But yeah, I think in football there are a few positions where you can pick it up pretty fast if you're a freak. That's why the Antonio Gates' and Julius Peppers and all that exist. But there's plenty of guys out there that are just as athletic as guys like that but can't put it together for whatever reason....which is why recruiting isn't that easy. It's all that other stuff that people can't seem to quantify that are the real difference makers. I really don't think evaluation has improved at all over the years.