Settlers 1/2 are logistics simulators. The core of gameplay is that the map consists of vertexes on which you can place flags, and then connect flags with paths. On each path there will be exactly one porter, who will carry stuff from a flag to another. Arranging your network so that goods get where they are going in a reasonable time is like 90% of the gameplay.
Exactly. It looks like a RTS but it wasn’t originally.