So we can know for sure that those who stay think that the CEO made a good decision in this regard, simply because they declined this offer?
A lot of people just view their job as a thing they do for the compensation. Taking the offer or not is about the opportunities and struggles they'll be facing either way, not their personal feelings about the company.
I really like my current employer, but if they offered half a year of wages as severance I would take the deal without a second thought.
I can't fathom why anyone would refuse such a deal.
It depends on how you assess the risk. If one is certain that within six months they will find a new job that is as good as, or better, than their current job – sure, why not? But some people might come to the conclusion that the risk is too high. Especially if they like the role/team/company.
Switching jobs also carries “transaction costs”. Doing interviews, perhaps LeetCode tests, etc, can be exhausting.
Another factor to weigh in: Many companies do RTO now, so if Automattic offer 100% remote work, that itself is a pretty good selling point.
With these considerations in mind, I can see why some employees will opt to decline the offer.