I think that the Blades would be a lot smaller due to the extermination and evacuation earlier on and so not so much of a need for them. That would mean that its a lot easier or them to simply pen us in than go hunting for us. So I can't imagine lots of them running around, making the pickings poor for hunting. Also I can't see Jack being all that interested in hunting Blades, just avoiding them. It's easier.

EDIT: Also Cynder, just wanted to be clear it's your campfire Jack is in front of.