If the game was canceled there would be no real reason to keep saying otherwise.
It's one title, with a likely niche audience, while coming out and saying it's a dead project after all of this time would disappoint those like myself that are still very interested in the game, anyone that is objective knows that concepts don't always end up in working out and if nothing ends up coming of the game then at least we would have closure on the issue.
My personal thoughts on the project, from my outside perspective are that the game is a much bigger project than people think, it's not just the one section of gameplay we've seen, maybe a very intricate world, physics, all kinds of mechanics that were just beyond the PS3's capabilities to pull off with the level of flair that Team ICO wanted and after the game had been attempted on PS3, once the PS4's hardware was finalized the project was moved to that platform.
Shuhei Yoshida has said the game was being re-engineered, so moving to a new platform would constitute re-engineering, expanding beyond one form to another (going from a smallish project, to a far bigger one) would also fit with that definition.
It has taken time for PS4's API to mature enough for the developers to make the game they wanted to make and unless it's the game they want to put out we won't be seeing anything of it, until it is.
Given how capable a system PS4 is, with the ability to pull off as stunning worlds as the likes of The Order I think the time may be almost here for the game to be unveiled again.
I honestly believe we'll be shown new footage of the game, perhaps at GDC, because it is a developer's conference, a place where developers can really talk about their journey in making their games, so it would make sense for TLG to be re-unveiled and for Sony to finally talk about why it has taken so long for the game to be ready for the public.
I get the impression that this game won't be shown off again until it is very close to going gold and nigh on in the perfect state to release it. If not GDC then E3.
As for the whole trademark business, Marty Sliva from IGN has said that when he traveled to Sony Japan to play a Bloodborne early build he did ask about The Last Guardian and it's now being called Trico by the developers, Trico is the name of the Griffin like creature.
Trico could be just the codename for the project, perhaps with Guardian or something closer to the original The Last Guardian being the final name for the title.
I do wonder why the game would have to be called The "Last" Guardian, making it seem quite final, hopefully we'll find out soon, Yoshida has said Sony has a time in mind for when they want to re-introduce the game again, hopefully that means this year as it does seem like a fair few big games will be shown throughout this year, like Guerrilla Games new title Horizon, Gran Turismo 7, Media Molecule's new IP, amongst others.
I suppose we'll find out at some point.