Cory, I guess what I'm uneasy with is the idea that we can separate out innate talent from all the other factors that influence performance. There are so many variables, and however well we know a student, we are still on opposite sides of a divide. We don't know the half of what us going on in their heads.
It's not horrible to set limits on what we see our students achieving, and as you say, sometimes it's a struggle to get somebody through a degree at all. But all the same I do think talk of innate talent is potentially dangeeous. Your son ended up in top sets, which is great, and he must have had great teachers and support at home, but too often students will perform in line with people's expectations, either because they don't have the confidence to think they can do better, or because they aren't given the chance to show what they are capable of. My daughter turns into a rubbish swimmer during school lessons, they don't expect anything of the kids so a lot of them, including dd, don't see the point in bothering. They proudly gave her a 5m badge the same week she got a 600m badge in her after-school lesson!!
I'm not suggesting you don't give your students your full support, obviously! Just that assessments of innate talent seem a very shaky basis on which to predict student progress.
The same applies higher up. Re your comment about not rising right to the top of your own field - I'm sure there are many reasons you aren't (perhaps wanting a life and to see your kids occasionally?:)) - but I doubt innate talent or lack of it has much to do with it. One of the most brilliant scientists I had the privilege of knowing was doubtless very clever. More importantly though, he lived his subject and had always been encouraged by his parents to believe that dedication could get you anywhere. A hard problem was an excuse to get stuck in, not to doubt his talent because he couldn't master it immediately. The archetype of a growth mindset, in fact