I understand what you are saying.
But if your premise is a gk doesn't have the all the skills and training to be elite because they are missing the "higher level stuff" then you would have to say that same thing about field players at u10 as well, because at u10, field players are missing a lot of higher level stuff as well. Not even necessarily higher level, but simple things like checking the shoulder....how many u10 kids that play midfield constantly check their shoulder? and how many of them check their shoulder and understand why they are checking their shoulder? I haven't seen many do that, or know why they're doing that.... so does that mean there are no u10 ELITE midfielders in the world? No, that's silliness, your definition of elite is a little off
Elite isnt defined by a specific skills set, it has to be defined by their ability compared to their peers. You start by looking at the world class level, look at all the gk or midfielders that are at the top of u10, in the WORLD, then you can identify where each kid would fit on that world scale...those players that are BETTER than others at their age group are the ELITE players.
No I'm saying that at U10 they aren't just missing the higher level stuff, they are missing the basics. You might have a natural that is better at some aspects (maybe the kid can kick real far, for example), but what they are doing isn't really goalkeeping technique. There are 4 archetypes for goalkeepers at this age (at least on the boys side):
1. The super big kid. Put in goal because may not be able to play the field as well and just blocks more of it. Unless puberty is kind, that kid won't be playing at U13, because at that age they need to start extension diving and you can't do it without being more athletic.
2. The super athletic kid. Can block shots directly shot at them and hustles for the loose ball and maybe plays out of the box. Still, what they are doing isn't "goalkeeping"....it's defending in front of the goal.
3. The wanna be goalkeeper. Is doing goalkeeper training but their trainer is teaching them to dive safely, not effectively. You may see them dive but balls are still sailing past him. May give up more goals than 2, but this kid is actually more advanced than 2.
4. The rotater. Coach doing it right...rotating a bunch of kids through goals to give them some experience, see who has talent, and who might want to continue it after U9/U10 to get them some training.