Sony is used to giving vague, "Yes, it's totally in development! Believe!" messages when harassed enough about The Last Guardian. In turning of the tables, former development head Yasuhide Kobayashi took the initiative and brought up the game at Tokaigi 2015.
He was asked to write down some favorite words (a Japanese tradition in which celebrities write messages to fans by selecting their "favorite words" of the moment), and out of nowhere, he chose "The Last Guardian," or at least, he wrote the Japanese title, which is "Bunch of Lines Going Everywhere."
Kobayashi has no updates on the status of the game and is in fact no longer on the project as he once was. He brought this up because he said that it was special to everyone. Despite hardships, he wants the game to be made soon.
Blog GameKana mentioned that big Japanese sites like Dengeki didn't even mention this in its coverage of Kobayashi's speech because "They've been through all this before, lol."
That, to me, sounds like it's been sitting idle for a while, regardless of what Shuhei Yoshida keeps saying. That sounds like a sad guy looking back at something dear to his heart, that he knows might not get made. Buuuuut I could be completely wrong. Prove me wrong, Sony!
Please. Prove me wrong.