Kishimoto actually said that? ROFL. It reminds me of the time Oda said that he wouldn't make One Piece as long as Kochikame. I've always wondered whether he meant "as long as Kochikame is now when I'm writing this" or "as long as Kochikame will ultimately be when it ends". Because he wrote that in the foreword to Kochikame volume 122, and it's looking more and more like One Piece will end up that long, though not to 160 volumes.
I've actually thought for a while now that Naruto would be about 500 chapters and that's it. I mean, with the Kyuubi plotline in the process of resolving itself, and Konoha destroyed, the way I see it, all that's needed is for this arc to turn into a grand battle against the Akatsuki, then have Sasuke come in the middle (he's an Akatsuki anyway) and have him and Naruto work out their issues, and then spend a few chapters on the aftermath and Naruto becoming Hokage. I think all of that could get done in about 50-60 chapters, Kishimoto has never really had pacing issues, so he could get it done in a year to a year and half.
I'd definitely say that Naruto will be the first of the Big 3 to end. One Piece is only about halfway there (I say about because they haven't technically crossed the Red Line yet, and there's a chance of Oda's pacing getting out of his control again, though I don't think he's going to let it happen again) and Kubo has no intentions of ending Bleach any time soon, not to mention his lack of the pacing skills required to end Bleach within the next 2 years. I can only imagine the effect on the ToC. I mean, Naruto doesn't sell as well as One Piece, but it's rather close, certainly more in that league than Bleach. It IS the 4th bestselling Jump series of all time (beaten by Dragon Ball, One Piece, and Kochikame, in that order). Losing it would be the first real blow to Jump's establishment since the Big 3 began to take form about 6 years ago. Though two years from now, Toriko may be primed to replace it. I doubt Bakuman will ever get that high, though. I still see it as a solid second tier cult series. I see almost everything as second tier at best if it isn't action/adventure, though. That's what traditionally sells best in Jump.