Assume a homogeneous group of people
When you have a group S of people, you interpret the characteristics that you observed that element X had as if the whole group S had them way of thinking. For the most part, this is just a misunderstanding, since groups of people are rarely homogeneous
Example
I hired a consultant and he came in not good, the consultant is not good.
For example, if you're a new client and it's not important to continue doing business with you in the future, it's reasonable to use your business as a test bed to train younger people and experiment with high-risk methods.
It is merely a mirror reflection of your business not being good enough.
My former consulting colleague X is not good, consulting is not good.
It's not clear why that X left the consulting firm, but with the "Up or Out" (promote or quit) personnel system, there are a lot of cases where people who didn't get promoted leave. I think what you are observing is someone who "didn't stay behind".
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