We are tied up alongside in the river port of Nuremberg, famous for the war crimes trials, the enormous Nazi party rallies, and more. There is still river traffic this far upstream, but it is like maybe a ship every 30 minutes. Closer to the sea it was more like a ship every 3-5 minutes.
My guess is that ship operators find the many locks on this part of the journey tiresome, expensive, and slow. If I was running one of those family powered barges I would charge a steep price for a trip that included the Main Canal. If that is the norm, then fewer cargos will merit transit on this waterway and perhaps the time-is-money charge drives more cargos to truck transport in this region.
We are told that following Nuremberg, we will soon be in the downhill set of locks taking us to the Danube,, which regardless of the song, isn’t blue. There are said to be fewer locks ahead of us than behind us, perhaps because the headwaters of the Danube is at a higher elevation?