Why are decisions "made" instead of "done"?

Typically when we've decided something, we say we've "made a decision". But why is a decision associated with the verb "to make"? Nothing is being made. If anything, it seems a decision should be "done", and associated with the verb "to do".

Why do we make them instead of doing them? Or deciding them?

For me it has more to do with intent vs action. A decision is made but that does not mean that the deed will be done. A decision is a thought process, not a physical action, and it comes before the action is completed. The verb "to do," implies an action with a result or, conjugated, describes an attribute.