You might want to look-into how first-responders handle leadership. Ideally, everyone who eventually shows-up to help handle the fallout of a crisis-situation is properly trained to co-ordinate things, but you can't know who actually will handle things until someone steps-up. As a result, the first trained-AT-ALL person on-scene gets the role, period, until they defer, delegate, or resign.
This leads to a lot of top-down and peer-pressure in related-fields to always be training. Leadership-training is often one of the cheapest, only-free, or even travel-room-and-board-included options available.
What they've found is that those who step-up lock-in on what needs to be done - all levels from the bottom-up have the idealized overall picture, checlists, exception scenarios hammered-into them, and the importance of keeping-track-of-and-share the details even when you don't have time to write them down or explain them to everyone.
Therefore, a lot of the related Leadership training revolves around how to document what you can, the importance of finding a replacement-for-you candidate who is paying attention and can understand what you would need to pass-on with minimal explanation. Thus, the person who you eventually defer to, who relieves you and takes charge is usually not the highest-authority or most-experienced person on hand.
The higher you get in these authority-chains, and/or the more experience you get, the more the job is literally stepping back and check-boxing all the peripheral tasks. Taking-up slack or identifying those capable of doing so and stearing them towards those roles while avoiding interfering or conflict-with the ... err ... "situational" leader that stepped-up first and hasn't bowed-out yet.
Mind-you, none of this has anything to do with the day-to-day of those involved. People have managed large-disaster-fallout situations for 24-hours-plus only for it to come-out later that all they had on their CV was CPR training and an un-related-job with no prior leadership experience - they may not have even realized that they were in-charge until asked-about it days later. People just kept asking them what to do, and when asked what to do by them, responded, "do you mind handling things a while longer?"; They signed whatever was presented to them and not full of errors, maybe not realizing x document wasn't just a witness statement.
I guess what I'm getting at is, yes, some people have natural leadership talent, and some people you can train in the role five-ways-from-Sunday and they won't be suitable or want to step-up, and yes, so much in life requires "that guy" to be in-charge of x location or x situation for whatever time-frame, but ...
... the inevitability of the need for a leader does not require the same person be in-charge of whatever for years at a time, months, weeks, or even days at a time. Every leadership role has a hand-book of-sorts, a list of known exceptions, exceptions you may not want the wrong-person handling, and essential, bare-minimum tasks...
Here, I think the First-Responder outlook has it right: everyone gets repeatedly trained for leadership and constantly scrutinized for suitability. There are EMT's, Fire-men, and of-course Police Officers who are not allowed to work alone(far from just trainees any-more, but not leaders ... Barney Fife?), and preventing them ending-up de-facto in-charge of something important, at least on-the-clock, is a big part of why.