Early career me thought that being indispensable was a good thing for career safety and leverage for promotions and whatever else, but that turned out to be far

Early career me thought that being indispensable was a good thing for career safety and leverage for promotions and whatever else, but that turned out to be far from the truth. In my experience if a company is so incompetent as to allow a single person to genuinely become indispensable, they're also so incompetent as to barely know it, and do nothing about that person leaving. Only after leaving will the fires really begin (or intensify), which is probably just a variation on business as usual anyway.