I think it has a lot to do with the size of the organization. If you're at a relatively small company, it's not that hard to identify and retain the top performers.

If you're at a faceless megacorp, that's a different story.

You can be laid off at small companies too. For example, a company may be running out of runway and it's looking increasingly likely the next round of funding will not materialize in time. It needs to control expenses and extend runway an extra 6 months, but everyone's a "top-performer". Who gets laid off? It's likely going to be those adding features (e.g. product folks), not those maintaining the business (accounting, devops). We can get into whether it's a good idea to kick off the death spiral for a company in that way, but my point is that no one is immune to layoffs, not at any scale, except maybe the founders.