It seems like for as long as I've been really a fan of Rush (around age 14 with Grace Under Pressure release), with each new release I hear some speculation or rumor that it is to be their last. It is funny that even back then, when Power Windows came out, they had been around what seemed like a very long time and had enough albums for people to speculate that they would be hanging it up soon. And there will always be some track on the album that might, if you are looking for it, seem like some kind of swan song moment.
So, yes, one day the speculation will be right. Even a broken watch is right twice a day. I just think it is funny how long I've been hearing it.