"Inu Yasha" is published on "Weekly Shounen Sunday" along with "Detective Conan" and "Tenshina Konamaiki". "Inu Yasha" and "Detective Conan" are the two top main attractions of "Weekly Shounen Sunday" magazine. It'll be a great loss of readership if "Inu Yasha" ends. There is a lot of pressure(?) from readers and editors to prolong popular manga as much as possible. Right now in manga, "Inu Yasha" is searching for the last piece of "Shikon no Tama". It'll be funny if it breaks and scatters around the world again ^ ^;
A couple of manga suffered from editors' pressures (I know) are "Dragon Ball", "Slam Dunk", "Yuu Yuu Hakusho" (all from "Weekly Shounen Jump"). "Dragon Ball" was originally planned to end after "Freeza" episodes, but was dragged much longer than that. The author of "Slam Dunk" wanted to end the story after main team was defeated at the national tournament, but editors wanted to continue the comic. So rather than putting "The End" at the last page, it was written "Chapter 1 End".... "Yuu Yuu Hakusho" ended quite abruptly. I heard author was so fed up, he didn't want to write it anymore. Anyway, "Weekly Shounen Jump" is quite famous for dragging popular comics until authors get exhausted. Right now "Naruto", "Hikaru no Go", "One Piece" are the main attractions of "Weekly Shounen Jump". I'm pretty sure it'll run for a looooong time.