[ken]

That is indeed a powerful mechanism -- but it still sucks to be a beetle, especially if you're not on a dominant branch of your family tree.

Imagine you had the job of recruiting beetles. You'll die soon, and your offspring (if you have any) probably will, too! What's the upside? Your species will be stronger for your death! That's a pretty tough sell. You're going to get the young and ambitious, and they're going to fight each other as much as they possibly can.

That's not the only way to win, or even the best. Pine trees are genetically successful, too, and they don't go out and murder each other.

I wouldn't complain that there are too many kinds of beetles, but I would complain that there are very few trees. It would be sad if beetles were the highest form of life on the planet.