> 2. The lack of a visible dip does not mean the internals are healthy. Often layoffs are accompanied with an expectation to "do more with less", which generally means the conditions going south for remaining workers.

I've always wondered: If the layoff is happening because the company over-hired and the roles are no longer needed, then why do existing employees need to step up and do those roles that the company just said are no longer needed?

Highly depends on the company and how they select the people to be laid off, but the issue can be that the layoff targets some % of over-hiring, and some teams are effected more than others depending on the makeup of those teams, project load, etc. Some teams are disproportionately impacted.