Roads have a way of getting improved as commercial activity demands. Don't plan on it "always being limited." Civilization follows access, and access follows demand.
The Bloodvein is on a lot of bucket lists and many are getting it crossed off with the easier egress at the end. It gets a lot of paddlers from around the world too. Not "too crowded" by any means. In 2017 we portaged back into it from the north and spent three days paddling back into Ontario and going upstream means you see a lot more canoe parties.