I like this post. It has the right balance between uncomfortable reality and some humour!
All middle managers (in my experience) talk a big game about reducing/preventing key person dependencies, but on 100% of my teams, there were always multiple key person dependencies. The real issue: If you are not the key person for anything, you are the easiest to layoff (fire).
Your uniqueness is not tolerated, assimilate to the collective, follow the processes given to you, don't think individually.
Except when solving these problems, they require creativity, be creative. BUT ONLY HERE