If you don't want to pay extra, you have to book six months in advance and be familiar with the fare system. It's super frustrating. It's just a train ride. I don't want to have to plan and organize it like buying a new car at the best price or trading stocks. And in the end, you can't even count on arriving on schedule. If you're unlucky, you'll be stuck at the train station in some godforsaken village.
I prefer to travel by car. The travel costs can be easily calculated based on the price of gas and fuel consumption. The total maintenance costs for a car are transparent. You are much more flexible and autonomous when planning your trip. The probability of arriving more or less on schedule is almost 1. And if you do get stuck in traffic, at least you have a little private, quiet, warm, and dry space around you.
If it were reliable, inexpensive, and uncomplicated, I would still find it more sensible to travel by train. But that is far from being the case. Instead, DB manages to combine the disadvantages of administrative bureaucracy and market economy.