According to Sony Worldwide Studio President, Shuyei Yoshida, The Last Guardian was never on hiatus.
In an interview with GamesIndustry, Yoshida said "It was hiatus in terms of releasing new information. The game has never stopped, the team has always been here. They're going through the re-engineering of the game, so the team size is smaller, because it's more engineering focused right now."
If the company is re-engineering the game, there is a chance it will be ported over to Sony's next-gen console. With development this long, it makes no sense to start reforming the game at this point.
Similar to what happened with Final Fantasy Versus XIII, the company might decide to make it an early release title for the PlayStation 4. It would be a strong selling point for the console and would bring in a lot of hardcore gamers.
Team ICO is famous for producing quality titles (Shadow of the Colossus, ICO) and have a strong following in the gamer community.
The Last Guardian has been subject to numerous delays. Announced back at E3 in 2009, the game has been pushed back year after year, with little information being released in the last two.
There is still no scheduled release date. Hell, there isn't even a release window.
You can read more about games with long development cycles here.