I added an edit regarding the definition issue just before you responded. Anyway, I'm just going by what I perceive most people to commonly mean when they think about athletics. This is from Merriam-Webster:
ath·let·i·cism | \ ath-ˈle-tə-ˌsi-zəm \
Definition of athleticism
:
athletic ability : the combination of qualities (such as speed, strength, and agility) that are characteristic of an
athlete
Sounds pretty close, if not exactly the same, to what I said above. I wasn't trying to make an exhaustive list of attributes, just list some of them. Soccer-specific skills aren't usually what people have in mind.
What I meant was that someone who is exceptionally strong, fast, tough, powerful, can jump high, run fast, has great endurance and is very coordinated will have advantages at almost every sport compared to people of similar skill level and experience. Someone with great soccer-specific skills won't necessarily have as much of an advantage at other athletic endeavors as our hypothetical perfect athlete.
I'm aware all sports place a premium on specific sport skills and also on general physical qualities. I just think soccer is more biased towards the specific skill side than the purely physical side than many others.
Regarding point 2)
I think China, Russia and many of the Soviet countries produce incredible Olympic weightlifters and gymnasts. That's a pool of about 2 billion people. The level of exceptional athleticism in those sports is insane imo. Parts of Africa and Jamaica produce the best track & field athletes in several events. That alone is about half of the world or more.
India has about 20% of the world's population, but they don't excel at almost any sports. Maybe hockey. In places where athletics aren't as culturally important, you won't see as many great athletes produced. Russia, China and the US place an exceptional premium on athleticism compared to other countries, so I don't have many qualms saying that they have most of the best athletes (but not all), together with some African countries. I'm South American btw, but we don't produce much in large numbers outside of soccer and some basketball. There just isn't a culture, infrastructure or an economy conducive to that over there.
I agree that comparing extremely different athletes e.g.: the fastest guy vs the strongest guy, doesn't make a ton of sense.