I agree at the first-line manager level (which this article is about), it's tough to get hired from outside, so getting the same position somewhere else after a layoff will be a tough job search.

My comment was more on the next levels - there seemed to be about as many high-level technical roles as managers (paid similarly) where I worked in biotech (that might be a different situation for software-only companies.) And there were more Directors/VP's than Principals/Fellows for sure. So at some point the "ladder width" crosses over.

And if you get laid off as a senior IC, good luck getting hired into another IC position. Age discrimination is real. The robust network is a must for anyone, manager or IC, in this case.