Very true.I think you have to consider the wider picture. Someone wanting to be in a quiet space for a three or four hour journey isn't necessarily representative of the rest of their week or their general demeanour.
For example, I may be travelling after doing a job that involves interacting with a 3-figure number of people, and on my way to a social event such as a forum meal, I may want to just be quiet on the train, listen to music, catch up with some other work or just relax. If I'm travelling to London I'll often book an individual seat for this reason.