Given that a very similar ticket already exists in Germany, they could have just told the DB staff to accept the French ticket as equivalent.

Stuck in the pipeline, for whatever reason. Lots of the surrounding EU regulation also doesn’t make sense without having a unified European ticket system as things like “a delay made me miss the connection, provide alternate transport” doesn’t apply if you have two tickets.

The situation in Germany is only going to get worse in the next decade, the reason being that they’re finally investing money in infrastructure which means lots of construction sites. We should be moving more cargo onto rail but fact of the matter is the rail links are already over capacity as-is. It might come to the point that Hamburg is going to build truck infrastructure at the shunting yard to get trucks off the harbour streets. At least the connection to Scandinavia is sensible, it’s been carrying Denmark-length (835m) trains since 2012 and the Swedes are currently fixing their infrastructure. Meanwhile Switzerland is loudly thinking about using Italy as a port because Bavarian-run federal transportation ministers like nothing more than building Autobahnen at the expense of rail. There’s a reason why “Hinterland” is not only a technical term, and not a nice one.