You said:

> In a world [where] CT logs and CAA records [exist]

And we are in that world. CT logs and CAA records exist. They are around. What you are implying you said is:

> In a world with CT logs and CAA records [and everyone/everything reads and validates them]

We are not in that world, and we probably won't enter that world for the next 15 to 20 years because we are also in a world where folks expect networked devices to be able to communicate (mostly) securely without constantly communicating with a centralized set of clearinghouses arbitrating "what is secure".

As we are discovering, our flawed systems may need broader rethinking, especially if we want secure communication (with all the epistemological ball of yarn that comes with it) without constant total centralization, which seems to be the approach-of-least-resistance lately.