I remember commenting when Mudge was hired that Twitter/Jack needed someone of that profile to offset his massive organizational weight as a founder, where Zatko would have the technical and community cred to make decisions for the entire org without, a) other people going around him and trying to get Jack's attention, and b) to demonstrate there is no doubt about the competence of the security team of the platform to satisfy some regulatory risk. I also thought it sounded like a bit of an overpowered choice for the role, unless it was not intended to be long term, and mostly as a tactical near term solution. That may have forshadowed this development a bit as well.

Into the territory of startup fanfic, I'd assert from Agrawal's perspective, he needs his own team, and a top technologist indexed on engineering competence is overpowered as an individual at that level - and for the agility the CEO will need for the next stage of his company. He needs his own people to execute for him. The company is no longer a startup, and its explosive growth phase is behind it. Now it's an asset to be managed, and doing that is an orthogonal set of skills to building and managing growth, so you need people who operate aligned to a longer horizon. The previous CEO's tactical super-hire isn't necessarily going to be the same asset for a new CEO's strategy.

It's odd to comment on this like its sports writing, but that's effectively what following these companies is. Knowing very little about the individuals, I don't need to mind read, as there are clear external incentives for this that make it a fairly neutral change.

When you inherit a powerful asset like that, as CEO that can be double edged. It's great to have someone that amazing around, but if they can undermine the momentum in your leadership even (especially?) unintentionally, while you're driving a massive organizational change, the choice really makes itself independent of the individual characteristics of the people involved.

Ceasing to work at twitter is probably the least interesting thing Zatko has ever done, so I don't forsee this reflecting on him at all, but before there are drill downs on personalities and culture stuff, it's worth looking at it from straight business incentives.