Rumours have surrounded the oft-missing Last Guardian for quite a while. With no media updates and only the occasional hint that the project was going ahead, people presumed that it was either on its last legs or that it was slap bang in the middle of development hell.
Eurogamer may have found the reason, reporting that Fumito Ueda has left Sony, finishing The Last Guardian on a freelance basis before moving on to his own projects. The fate of the people at Team ICO is yet unknown, but presumably Sony will opt to keep the studio alive – depending on reaction to The Last Guardian.
It's unconfirmed if this is true and I wouldn't dare hazard a guess as to why he'd leave, but I'll be keenly watching this space over the coming months.