So mostly people are talking about virus which can be actually identified and studied. Up until very recently this was pretty much restricted to those who repro

So mostly people are talking about virus which can be actually identified and studied. Up until very recently this was pretty much restricted to those who reproduce massively and leave at least some clues. We know next to nothing about benign virus in eucaryote hosts (or at least I don't). Also, I don't think "benign" virus compete with pathogenic virus for anything. This may seem strange, but unless the organism is completely shutting down, and probably not even then, only an extremely small fraction of cells are infected by any one virus. That's why you still have a nose after surviving the flu. Any competitive mechanisms would have to be more complicated.