I don't think that performance feedback or reassignment has necessarily anything to do with it. Would you like to be frequently reassigned at your job? I don't know many people who would.
Yes, all these things might create entrenched groups, but make working viable in many occupations in the first place. I would take the groupthink in that case too.
In a company that is successful and growing, with new teams and projects and offices, there will be more promotion opportunities per candidate - and fewer situations where they have several strong candidates and an almost-arbitrary choice to make between them.
If you're in a sector that isn't growing, or might even be shrinking, I imagine promotions are a lot more competitive...
Admittedly, 'reassignment' might not be the most precise term for this...
The issue is not lack of possible promotions. The issue is who the opportunities goes to. In a growing company, the friends, family and "one of us" will still be more likely to be get the good stuff.
I'm not saying it completely eliminates bias by any means, but I've worked at a company growing from 200 developers to 2,000 developers - and getting promoted for me has been a heck of a lot easier than my friends in fixed-size organisations.
When you need to find that many trusted, competent managers that quickly, you can't afford reject people on the basis of their surname :)
I left startup because it was like the worst experience I think I had regarding gender (I am woman). Not that they would be toxic out right as tech bro stereotype, they were not. Generally they were good people.
But the lack of process and inexperience basically amplified the bias. There too much guess work going into decisions, so they were primary based on pattern matching like things. People were making decisions on very little information and in ambiguity, which made all the assumptions matter more. Where while bigger company I am in now, while there are people who openly express sexist opinions, in general I think I am getting more equal results.
Mostly because once they are making the decision, it is more likely to be based on my actual track record rather then feelings. Not that it is perfect, but when it is unfair, it unfair in all kind of various ways toward everyone and it seems more random. More likely based on personality conflict or something of that sort.
I wasn't so much using it as a proxy term for growth, but rather as a direct description of work culture.
I've worked and consulted at a variety of companies. Of the ones that had an expectation that you do 1-2 year stints on teams, then rotate to different teams and challenges, I would describe ~100% as having a healthy workplace political culture.
Of the ones that did not have that expectation, and people typically stayed on a single team for 2 years+, I would describe ~25% as having a healthy workplace political culture.
My conclusion is that, more-so than anything else, cultivating and encouraging regular internal transfers produces healthier companies. (And that's not even broaching the documentation and repeatability benefits!)
It seems counter-intuitive, and I never would have guessed if I hadn't seen it again and again...
Yes, all these things might create entrenched groups, but make working viable in many occupations in the first place. I would take the groupthink in that case too.