I have heard this opinion over and over again but it just hasn't been my experience. I've spent a lot of time in both Berlin and Munich over the last couple of years and I never waited more than 10 minutes for a train
The cross country ones aren't really of interest to me. Those don't move a whole lot of volume. The inner city transportation such as the DART is what most people use and it's punctuality rating is closer to 70%. I'd love to know how they measure that though because I took the DART 5 days a week for months and it was not on time far more often than it was. The people here literally don't bother checking the listed times because they're wrong. Show up at the station and pray one arrives within the hour
When people talk about Deutsche Bahn being unreliable, they are talking about the cross-country regional / ICE network, not city rail (S-Bahn etc in Berlin, Hamburg are frequent and pretty reliable).
You may have had a good experience here in Germany as a tourist, but it's simply not reality. Trains are not reliably on time here these days, and it's a huge problem.
I do not doubt the DART is unreliable in Dublin, the buses are just as bad (I moved to Germany from Dublin a little over a year ago). I know it's a bit apples to oranges comparison between Germany and Ireland, but I can assure you, it is bad here in Germany currently!
I've had terrible experience with intercities train with delays that were more than 25% of the length of the trip. Once I was waiting for a train that was an hour late. The next train on the same line even arrived before the train I was waiting.
I've traveled in a lot of countries and used train in a lot of them, none of them have been quite as bad as DB when it comes to reliability.
And the recent articles that claim only around 60% of trains arrive on time bears that.
