Naruto has 22 chapters left to animate. If you include the Gaiden sequel (which any reasonable person would, since it's also hand drawn and written by Kishimoto), 34 chapters left to animate.
If you covered 3 chapters an episode (a nice fluid pace, but these days anime tends to go at 1 or 2 chapters an episode instead), it would still require 11 episodes to finish the Naruto manga. If it's 2 chapters each, that would be 17 episodes. Even if you only cover the main line Naruto manga, at 2 chapters a piece, that's 11 episodes. At 3 chapters a piece, that's 8 episodes.
There aren't 8 weeks left in the year for Naruto to cover the rest of the manga. Much less 11. Much less 17. Instead, all of the fall season is pre-scheduled for some random Jiraiya filler. Even if it comes back to canon Naruto in November it'll be too late. But I don't expect a single episode of Naruto to be canon this fall. Why bother? The entire year has already been wasted on filler, so why change anything now?
2015 has 52 weeks. Out of those 52 weeks, Naruto chose to air 10 canon episodes, and 42 filler episodes, to a story that had already been finished writing in 2014. There was no reason for 2015 Naruto to delay any longer. Waiting for the manga to finish first was already achieved in 2014. Even waiting for the Naruto gaiden to finish first was finished this summer. The fact that there's still filler airing in the fall of 2015 is simply inexcusable. There's just no conceivable reason left for filler to still be airing at this late date.
The Bolt Naruto movie already aired this summer. If the tv sticking around to motivate people to go see the Bolt movie were the issue, again there would be no reason for Naruto to still be airing filler this fall.
If the Naruto tv series wished to include the Naruto light novel epilogues, which are still approved and illustrated by Kishimoto and thus canon, that too is no cause for delay. The final volume came out July 3, 2015.
Even if, for some odd reason, you were to include the Naruto Shinden light novels as well, though they aren't illustrated by Kishimoto and seemingly have no relation to the genuine timeline anymore, there's still no reason to delay. The final Shinden novel comes out November 4, 2015. Even if you started making canon only episodes now, there's no way the anime would come out before the book was published.
There is nothing left for the Naruto anime to advertise or promote. The story is dead, done, finished, in every other medium except the tv anime. The Naruto Storm 4 video game is set to be released February 4th of 2016 (It was originally set to release this fall but got delayed). Are they seriously delaying the anime until the video game comes out? But even then, so long as they covered the canon Gaiden manga and the canon epilogue novels, the series would easily reach into February, and there would be no excuse or purpose for filler to still be being made at this late date.
The previous Naruto anime opening went for 26 episodes. The one before that went for 25 episodes. In that case, we can safely assume that the current Naruto opening, introduced last episode (ep 432), will also run for 26 episodes. And yet, in the entire opening, nothing of note is spoiled. In the previous openings plenty of canon content was spoiled/previewed in the opening, so you can't say they're doing that just to keep the suspense up. If they intended to show any canon content in this entire season, they would have shown it in the opening, like they have previewed in the opening all the canon content that was incoming in all the previous seasons. As such, we can take as a promise that for the next 26 episodes there won't be a single additional episode of canon Naruto. That will take us past the February 4th Naruto video game release date, without a single step closer to the canon ending of Naruto.
If Naruto wanted, with its remaining manga, gaiden manga and light novel canon content, it could easily have aired canon Naruto material throughout 2015. Even now, if it wanted, it could air throughout 2016 while relying solely on canon material. Instead, we've been essentially promised nothing but filler for the rest of 2015 and a large portion of 2016. Maybe in the spring of 2016 Naruto will return from filler hell, if we're lucky. Why did it have to be this way? What possible purpose does it serve to not end your series when the story has reached its natural conclusion? It's been so many years -- shouldn't you want to see it through to the end already? What if one of the voice actors suddenly die now? You had the chance to end it perfectly, and then suddenly that chance is gone forever. What about fans who are 70 years old and dying of cancer, and all they wanted was to see the ending of Naruto first, which they've been watching for all these years? Now they'll die, still stuck in filler, never having gotten to see the epic last fight between Naruto and Sasuke animated. Who will apologize to their graves?