Some of these roles are also where some very talented engineers end up who have decided they do not want to graduate to management positions. So it's quite possible they weren't refused advancement, they were offered it but turned it down because they wanted to keep working on [X] project instead of other products they weren't interested in, or managing people where that is a skill they know they don't have.
So it's quite possible they weren't refused advancement, they were offered it but turned it down
Absolutely!
Anecdata: I have 30++ years of experience. I enjoy programming. I do not enjoy managing people. I do OK managing projects, but don't enjoy it.
Especially in the first 10++ years, when I had my yearly performance review I would tell my boss "whatever you do, don't make me a manager." They tried talking me into management roles quite a few times (and succeeded occasionally getting me to fill a technical management role in projects) but have mostly honored my request.
If I had gone into a (technical) management role I would likely have made a little more money but my stress level would be a lot higher and my enjoyment would have been way way lower. I've watched other engineers that went the technical management route and have been very happy with my choice.
Staying heavily technical isn't the right choice for everybody, but it was absolutely the right choice for me.
That's actually part of what I meant with "Peter Principle awareness", although it is definitely not what I wrote. I actually believe that not wanting a management role (what you wrote) is far more common than getting denied despite trying (what I wrote) for the kind of people we are talking about here, those who may actually end up getting a high status non-management role invented for them.
