Its a lot easier for Apple to fix security issues within the Apple ecosystem than it is for Apple to pressure Adobe to fix the problem, port it over to the suite iOS/iPadOS/macOS, and distribute the fix to whoever needs it, as well as communicating the gravity of the issue, post mortem, adjacent attack vectors and surface area, etc.
I'm not saying you are entirely wrong about consumer lock down, but for various reasons, consumer lock down can be objectively better for the developer and user experience, and it is easier to move fast when you have fewer dependencies at play.
I'm not saying you are entirely wrong about consumer lock down, but for various reasons, consumer lock down can be objectively better for the developer and user experience, and it is easier to move fast when you have fewer dependencies at play.