> If I went looking for another startup to join at some point in the future, I would specifically look for an exec team or founding team that could cite examples of building up high performers for internal promotions — and swiftly recognizing and rewarding those already having impact outside of their role-defined scope.

Yeah in my experience this seems very rare. The default in most start ups I've seen is that when a new level in the hierarchy becomes necessary and/or available (i.e. the existing person leaves) is to hire externally.

I guess the rationale is that if everyone is doing some necessary job and they are good at it, it's better not to mess with it. But needless to say, I find this very demotivating. Much more so than if I am passed for the promotion but a colleague gets it, because I know that if there is a culture of promotion and progression, I might have a fair chance next time. But if its always external hires, then my whole career at this company is in the same position I started with.