It should have been obvious for a few years now that whatever "The Last Guardian" game that got revealed at E3 doesn't exist anymore. Whatever is being developed has long since transformed to ensure technically feasibility and at the same time take advantage of the power of the PS4. It might as well be a new game.
This game was a passion project gone horribly wrong. You can't churn out masterpieces like ICO and SotC, you need designers and developers to have a vision and a will to execute on that vision. The minute Team ICO wanted to disband and move on is the minute the game died, even if it does come out it will be garbage I'm betting.
As I recall, the trademark has lapsed before - until presumably somebody in the legal department sent in a check to renew it. But if they don't bother renewing it this time, the game goes from unofficially dead to really most sincerely dead.