Not sure if it would be techically possible to have gaps in the platoon after every five cars, but at least it would be trivial to set max size of one platoon to something reasonable.
Sure, yea, I don't mean like it becomes literally impossible to merge in. Just that for any reasonable size platoon, it disrupts more traffic than it saves. Given existing roads and the existence of not-platooned cars on the same roads, it doesn't really work.