Comment by munificent

I don't think we stopped doing it because it's gimmicky.

Recordings in the 1960s were mixed to be played back on stereo speakers. You can hard pan stuff and in your living room where you listen to it, it will produce a nice pleasant stereo image because each ear can hear some of both speakers.

Today, audio engineers mix music to be listened to primarily on headphones. If you pan something hard left, it's literally not going to be heard in the right ear at all which sounds horrifically artificial.

So now music has to be mixed to synthetize a pleasant soundstage when heard on headphones.