Well you are on the frontier of the playerdoms, so it's not surprising if you're dealing more with NPCs than PCs.
But it's in general easier to obtain access to players, so not a bad idea at all to see what openings there might be.
And placing unanswered NPC dispatches in the DO is also a good idea, with a note that no reply was received obviously.
Apart from that I wouldn't worry overmuch if I were you. You're not drowning us.