Unpopular opinion, more people are capable of doing well at higher level jobs than they are at low level grunt working jobs.
People who do well in higher-level jobs know /exactly/ what they're best at or uniquely positioned to do, and do that. Meanwhile, you need to delegate the rest to whoever's in the best position to do so (growing people if there aren't enough) which is itself a tricky calculus.
Everyone I've seen rise through the ranks has absolutely nailed communication, self-promotion, parroting the party-line, moderating their words, adapting to their audience, improving their speech techniques, giving excellent presentations etc.
Many, many people simply aren’t able to do that. You can’t manage complex organizations that include people without that ability.
Never thought about it that way, but I think you're correct. The number of adults who cannot hold their cool in the face of a perceived slight or setback is shocking.
The stakes are different
If it's easy for someone it's because they are special, and usually in my experience they're special in a sociopathic tendency kind of way, where the things that make being in leadership hard (having responsibility over so many careers, feeling social and professional pressure from all directions, fending off middle management politics) come much more naturally to them.