[dvdkon]

I suppose making yourself more than an immediately replaceable cog in the machine is part of what the author is advocating, ideally in a societally beneficial position.

Moreover, many businesses operate under the "everyone is replaceable" model, implicitly adding "without much effort", but that's not really true. There are plenty of examples of political movements that never recovered from their leader or figurehead leaving. You can't just take any other politician and swap them, their positions are too personal. That's an extreme example, but I think it applies to most job positions that aren't just about following checklists, in varying degrees.