I ought to mention that functional programming has been around for a long time. It's come back into vogue because it is a tool which is suited to today's distributed, multi-cored world, and, yes, partly because OO has often not delivered what it promised. But OO worked just fine if you applied a sophisticated understanding of what it is for. As another commentor mentioned, it is about behaviour more than about reuse.

Fail to apply a sophisticated understanding of a new paradigm and you'll just run into the same problems.