While it looks immoral if you don't understand the mechanics, people are simply responding to incentives around bankruptcy laws. Nobody wants to try to turn around a bankrupt company at their old salary (with their old RSU's and options now worthless). The real question is, should Chapter 11's even be allowed for corporations (as opposed to Chapter 7)? Shareholders vote for these because they know that in a Chapter 7…
So they quit, and someone hungrier + lower on the ladder gets a chance to prove themselves by turning the company around, rewarded by staying in the position when it's cushy again.
It rarely works in large ones. Especially for an abrupt transition. An effective executive, particularly on the commercial side, is a living walking Rolodex of internal and external relationships which are immediately no longer working on behalf of the company.
Worse, they may work against you. I've seen competitors come swoop up top sellers or sales leaders and have them strip mine the good accounts from the remaining customer base.