a) Tree communication graphs are known and proven to not provide reliable message transmission against an adversary. As a boss you (should) know and live that but most prefer to hear the flattery and see the grass as green until it's too late.
b) You have stressful knowledge as a boss that you decide to not share with your underlings -- usually because you don't trust them. Some companies have been known for their openness on every topic. We are talking about software engineering here not factory mindless work. If you don't share and bottle things you are doom ing yourself.
c) I am sorry but if as a boss you are unable to downgrade yourself -- tells me either you don't know you can hire another boss to be the CEO/..., you are inept and can't do anything useful in the company besides "bossing," or you live in an illusion.
Somewhere between the janitor and the CEO people stop working for their next meal. And few CEOs care more about employees future than their life's work.
P.S. That said being a middle manager in a growing or cash cow company means making sure the status quo remains. Thinking otherwise is the illusion I think a lot of people becoming middle managers have for too long a time.