There are multiple studies showing that paying volunteers can backfire in many ways. It could turn an hobby into a chore, attract the wrong kind of contributors, or sour those that do not have enough time to qualify for money. Plus, any metric you were to use to assign rewards would quickly be gamed by the wrong kind of people.

We can discuss about how much the administrators are paid and the many issues wikimedia has, but please, for the love of god, let’s not pay editors.