And honestly, they should. Managing a company through 50, 100, 150, 500 and 1,000+ employee milestones requires very different leadership skillsets. There are very few founders who (1) understand this (2) are willing to party ways with their company (3) can navigate through each stage without help and (4) would pull a Zuck and surround themselves with more established/senior people (e.g. Sandberg) as they hit those milestones.
I'm all for young entrepreneurs challenging the status quo by thwarting an old guard of seemingly "old people" (a la Jack Barker), but this is one area that traditionally has a lot of "old people" simply because experience is incredible valuable to scaling companies.
I haven't read "The Hard Thing About Hard Things", but my understanding is that it basically touches upon all of the intricacies of how to navigate business challenges that typically more experienced senior individuals possess.