You tend to know your spouse, you don't know the mental state of people on the train. Especially people who have already demonstrated they don't care about social norms or preserving tranquility in public spaces.
Someone blaring their choice of music in a public space at 90 dB is a “cultural touchstone”?
I don’t drive, I take public transit daily, and am old enough to remember when you would never experience anything like this (even in the heyday of boom boxes in the 80s). So yeah I’m not convinced it’s a “me” problem.
And returning to the point, if you asked someone 30 years ago to turn their music down they would either comply or say something nasty - not physically assault you.
