I agree with you. I think (and hope) there will be a part 3, and your reasoning was pretty good. Even if you consider it guess work and theories, I think your right about Masashi Kishimoto probably not wanting to stop an excellent source of money. I have some other stuff that looks like it won't be ending as well.. More or less..
This page says their source implied a movie for 2015 and possibly 2016 -You must be registered for see links
This site had a bunch of interesting things, but this quote is what mainly caught my eye. ''Also, a continuation to a bubbling love story within the series may be featured as well.'' Feel free to check it out -
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And then, there's this - "Shueisha, has promised fans that there will be additional “Naruto entertainment” scheduled for release in 2015. What that is, we don’t know, but it sounds exciting!" from -You must be registered for see links
We also have a countdown to a 'Huge New Naruto Project' said from -You must be registered for see linksand from here -You must be registered for see links
Both referring to this pageYou must be registered for see links
And finally, (this being a little guess work of my own) you can check out a small summery translated from the upcoming movie for December 6th (Naruto: The Last) and it doesn't exactly look like it's mainly to end the manga, more like just a good movie idea.. But who knows. It could possibly open up for a upcoming part 3 or just be a good movie to watch like Road To Ninja was. Read from here -You must be registered for see links
I don't know whether it's all concrete or not when added altogether, but I won't a deny that I am 'Hoping' for a part 3 like crazy, haha. I could very well be wrong, but I hope I'm not!
I absolutely agree!