Hate to sound trite, but it often is the culture. If people feel siloed it's really easy to fall into not caring very much if you're not intrinsically motivated to succeed. However, on a closely knit team, where you put in the effort to get them included and owning things and be supported by the rest of the team in it, many start performing better (even if that starts by just asking for help earlier) simply because they don't want to let the team down. Not always, perhaps, but I'm not convinced that "poor employees" are innately reflective of the individual, so much as the individual + environment. Certainly, I personally have been in environments where I was a rockstar...and environments where I mentally checked very quickly (and sought to leave as such). And the former were the higher output environments, I might add; it wasn't just me being "out of my depth" in terms of skills or similar, but rather me not doing well when I was set up without any real empowerment or support structure and still expected to at least put on a show of trying.

It's not trite and I wish people didn't need to feel like apologizing for it.

This has been central to my life the last several years, this culture and person-fit issue. I've seen it play out with friends and family and it's surprising to me it isn't recognized as such. A close friend went from almost literally rockstar status at one place, and moved for reasons that had nothing to do with him or where he was at. He completely fell apart performance-wise at the new place because he didn't fit in to the same extent, went back, and now is doing great again. I don't think the new place was bad, or him, it was just this poor person-culture fit issue.

My spouse was somewhere she was treated like dirt, never quite welcomed into the team (she wasn't the only one, but it was the case nevertheless), and then treated her like a failing employee when she wasn't acting the way they wanted her to (however that was). She left, and now is bringing in more money for the new company than any other employee, in large part in my opinion just because they actually let her be part of the team (this second place is actually a much larger company).

The experience of being siloed is awful, and even if you are intrinsically motivated, can be completely demotivating, because if it's bad enough, it leads to this feeling of complete loss of control where you're at. There's also all these little things that even if you're super competent, you might need help with, just as a function of being a human being as part of a larger organization.

I could go on with stories like this, but suffice to say I think in a lot of places management often doesn't look inward enough. I think the churn continues because for whatever reason the culture change is more painful for them to contemplate and implement than whatever losses are incurred by high turnover in a given position. The last place I was at had entire key units just resign completely together en masse, and the response after they left was "well I guess we're not good at [key function] so we'll just go on without that." In an important sense they had to narrow the scope of what they offer because of culture problems.

And yet we end up having these discussions of displaced employees not being "intrinsically motivated" enough, as if that happens in a vacuum.

I agree about culture being a big part. Though no clue how you can improve that in your team as a manager?

I worked for a company where my team was fine, and individual people from other teams seemed perfectly smart and capable when talking to them, but looking at their team's output, they might as well have been idiots. I image for many of them, if they had worked at a more functional organization like Google, they would have done good work. (Even if not to the standards that Google has. But certainly better than at their then current employer.)

As a manager, the big ones are making sure that everyone understands what is going on, and feels responsible for it. So if you see a silo developing, you intentionally break it, and explain to the team why you're asking someone who knows nothing about a particular domain to own the task (and also call on the silo to make themselves available to help teach the domain and answer questions and such). It means that task will take longer, but the long term health and effectiveness of the team will be increased.

That also includes manager context; ideally, even things that a manager usually does, the team starts stepping up to do. So working with product to define requirements? Manager should include the team with that and look to have them start taking ownership of it over time. Prioritization? Team sport, until it becomes as natural as breathing, and people are better able to prioritize their own time as emergents come in. Etc. This not only helps avoid the -manager- becoming a bottleneck that slows everyone down, but it helps individuals to grow really quickly and feel more empowered.