Again, I'm just an armchair analyst, but in that year of efficiency,his aim was to reduce wastage, removing low performers etc.

That kind of trimming entrenches previous culture even more, which can be desirable - but not in this particular case where the culture itself is the issue.

At that point you can't trim, you need to decimate. The layoffs at that time were several waves of around 10% - unless I misremember? If he instead did two waves with 40% each and slowly rebuilt from scratch, it'd be a different story.