Looking at Instagram there are undeniably many physically fit Americans. In reality their physical fitness is notable because it is relatively rare.
Elite universities are sustainable in an industrial society where scarcity of resources means there are only so many high positions.
In a post-industrial society knowledge is the resource. Elite universities then instead mean you have a lack of resources.
Err, no.
Don't get me wrong, the Oxbridge system accepts, fosters and matriculates some very bright, very smart people.
But that is not at all what the core of the "Elite University" system is about, it's about connections and maintaining a single degree of freedom between the families that collectively hold > 90% of the wealth, resources, and influence within UK society.
In a post-industrial society, or beyond that, you aren't tied to physical resource in the same way. Instead you are limited by the amount of people with relevant knowledge. The existence of elite universities in such a society is really more saying that you can't produce enough people and opportunities.
Arriving at a village finding there is only one person with a car you don't say "wow, this guy is successful" you say "ouch, this is a poor village" even if that is the most successful person in the village. Because these days we expect cars and if everyone had cars he wouldn't stand out as successful.
Pretty much any male politician whose official actions could be described as inhuman or sociopathic has been through boarding school trauma.