Sleep deprivation is classed as torture. Even if you're a Type A personality, 4 hours is not enough to avoid issues with basic cognitive competence (at best) and general mental health (at worst).
See e.g.
http://www.nytimes.com/2011/04/17/magazine/mag-17Sleep-t.htm...
While it's true that not everyone requires the exact, same sleep schedule or regimen, there is no human on Earth who can successfully go years and years on 4 hours or less every night. You'll pay that debt eventually, with interest. Maybe not today, and maybe not tomorrow, and maybe 20 years from now. But you'll pay it back. Often in the form of a heart attack, a stroke, or brain damage.
I am using conditional logic here because, like you, I have no idea what "invariably" really means here. Writers have a tendency to throw around words that sound good, without always considering the true extent of their meaning. As a sometime-writer, I suffer from this problem myself. "Invariably" is a tall claim, which is why I'd like to see the evidence for it before rushing to conclusive judgment.
Still, I don't see that as "unacceptable" behaviour. It's something to be frowned upon for sure and it would be great if she could be punctual all the time, but being the CEO of an incredibly large and diverse organisation, she could be forgiven if she was late due to some other meeting or work-related issues.
Also, remember she's getting only about 4 hours of sleep everyday and practically lives at her workplace, so I doubt she's being late on purpose.