Not liking this dichotomy

In academia, it's supposedly "publish or perish." Why?

In this particular case, a manuscript we submitted got a rather chilly review from the journal. I'm not sure whether the solution will be to substantially revise the paper, or to submit to another journal. We'll still have to figure that part out. But it would certainly nice to have an extra publication under my belt before I apply for academic positions (post-doc and otherwise).