Because it feels natural for 1.0 to be final. If it's halfway done it should be 0.5, plain and simple, then everyone knows where everything stands, where it's going and we don't need to have conversations like this one.
And I'm not saying I want it to end soon. Few weeks ago I just finished 0.95, and it feels like we're just getting to the best parts of the story, so more than anything I was worried it might come to some abrupt ending. I hope we'll get another few years of updates.
Anyways, thanks for the answers.