I don't want to reach too much, but I know a lot of Germans and work with Germans so here is my take:
After the 1990s and the EPO scandals of cycling and running, the Germans were the leaders in testing, busting, and reporting on drug use. They broke most of the biggest scandals through real journalistic work from the ARD (German news)
The knock-on effect is that Germans are cynical and disinterested. There is a "well, it is all a fraud" attitude about cycling, swimming, and track. Not to mention, in modern Germany, athletes cannot effectively dope (anymore) and as such they have almost no Sportler at the peak international level anymore. This fact has caused interest to drop dramatically.
Prior to the 1990s, the Germans were one of the world's track & field powerhouses. They averaged 10 medals per WC in the 1990s. In Budapest, they got zero. The days at the top are over. Uta Pippig, Dieter Baumann, Heike Dreschler, Heike Henkel, Lars Riedel, Stephane Franke, are all long gone.
The journalist Hajo Seppelt is a hero of clean sport but having no dopers in your country also impacts your country's odds of doing well on the biggest stages: OG, WC, etc.