Each airline would have to build their own system, which would be highly inefficient. If a third party builds it, all of the airlines can share the benefit. Al

Each airline would have to build their own system, which would be highly inefficient. If a third party builds it, all of the airlines can share the benefit. Also, I would imagine that a third party system would help by discovering arbitrage opportunities across carriers - when you have to bump passengers, you could offload them to another carrier with more availability.