I think there's a shortage of all kinds of bikes at the moment, regardless of brake type. Tourers are a niche market and they are probably even harder to find, and also they are now probably quite popular for people trying to get a "socially distanced" way of travelling.
Germany is a very special market. I live there but I'm not German myself, which gives me a great overview of both the local preferences and the international trends (at least on the English speaking world, the ones you read in forums and blogs). Sometimes they can be quite apart. A few examples:
-Vintage mtbs seem to be getting expensive everywhere and the good ones are hard to find, while in Germany most people have one forgotten in the basement, so they are just considered "old bikes" and can be purchased at decent prices
-Gravel bikes are of course also getting popular here, but Germans still prefer as they call them "Trekking" bikes, which are just up to date hybrid bikes, which are quintessential German: practical, affordable, they can go well in asphalt and on forest paths, most come with all the lights and reflectors needed to meet the strict local traffic rules (which is why giants like Trek or Specialized sell nearly zero urban bikes here)... Basically a gravel bike for the everyday rider.
-Touring bikes are extremely popular, even though the English speaking world seems to ignore it. Germans love to travel, and there are dozens of local brands which enjoy great success in their own and nearby countries: Patria, Utopia-Velo, Velotraum, Tout Terrain, Intec, Poison, VSF-Manufaktur... But here most tourers have flat or butterfly bars (instead of the ubiquitous drop bar in US/UK) and often a Rohloff hub, plus of course dynamo hubs and very powerful lights from factory. Many come with rim brakes, not only that, the expensive ones will often come with Magura hydraulic rim brakes.
Can spot the German or Dutch cycle tourist a mile off just looking at the bike and riding position. Not at all like in France either.
