That's exactly it. It's not because of some cultural bias or whatever.
I'm in Japan. I use trains because it's so very easy and it's so very reliable. It's simply the best option for travelling. If I wish to go to Tokyo? I check a website quickly, I look up the best connection for my schedule (easy to find), I may pay in advance, or not. I take my bicycle and go ten minutes to the nearest station, park the bicycle in the bicycle parking there, and off I go. As it's a small station I change to a limited express train (where I've booked a seat) after ten minutes, then, after another forty minutes I reach a big station and I switch to the Shinkansen and I'm off to Tokyo. I'm relaxed all the time. I buy a coffee on the train, and/or I buy coffee and lunch at the station and bring on the train.
Every other way of getting there is way more complex, and would take way more time.