This seems like yet another anti-spam measure that will not be implemented globally, therefore cannot be relied on, you still wont be able to strongly trust DKI

This seems like yet another anti-spam measure that will not be implemented globally, therefore cannot be relied on, you still wont be able to strongly trust DKIM/SPF as a ham indicator. Also, many people's filtering setups wont even be able to create the kind of relies DMARC requires, so they wont be implemented either.