Honestly it's a very low bar and Germans should aspire for better and not for a meager "we are not the worst there is".
I would say you need to compare DB to other Western European railway operator/networks. In my personal experience, DB comes dead last and it's not even close to the 2nd to last. Renfe (Spain), Trenitalia/Italo (Italy), SNCF (France) have much better services, at least on the long-distance routes (> 200KM). So much so that they are a viable alternative to domestic flights.
Additionally, most of those countries also have a much worse geography to contend with (e.g. Italy with the Alps and Appennini) and they still manage to have a nice high-speed rail network that works.
Finally, answering your last point, Japan still is THE role model. So much so that you can get stuff delivered to a train station your train is transiting through (at least with the Shinkansen lines) because the carrier knows exactly when your train will be there. I was astonished by that.