I worked in several startups, and in my last job we hired some new managers who quickly started replacing the old staff. They are also replacing experienced staff with former reports from their previous companies. So at this point they exercise as much power as they can in their function, and stop anybody who might have a different opinion. From one side, this is against our collaborative company culture, and is creating a bit of a toxic environment. But it's bad to replace them: "hey, Bob created a proper company function around himself, we didn't have any structure before, what do you mean we should let him go?"
From the other side, I have to admire their ability to entrench themselves: they amassed so much power that to remove them means losing a good chunk of productivity. And it's not the first time I see this: there are also bad performers who are being kept in the company, mainly because of their connections to customer accounts.
So, I wonder: is entrenching yourself the way to get promoted and have a successful career? Making yourself indespensable by not sharing information, not sharing contacts, not sharing responsibilities? I have seen advice against making yourself a bottleneck, but these senior managers seem to be doing well for themselves.
I see how successful all these managers are, and I need to understand if it's a standard behaviour. The only variable I can think of is company size. How does it work? Never be a bottleneck when you are a doer, then become am entrenched bottleneck when you move up?