Many recordings don't even record vocal and piano properly. They'll put the singer in the center, the keyboard player's left hand in the left speaker and right hand in the right speaker, so the piano spreads across the entire stage. They'll do the same with drums; half the kit panned right, the other half on the left.
I do find that annoying and know exactly what you mean. This is another reason mono recordings can sound so convincing. The better singer/piano recordings I have place the piano slightly behind and to one side of the singer. The singer is centered and the piano is behind and slightly off to one side, usually the left side. The piano's sound box becomes a nice backdrop for the singer. It is a very strange effect when the low notes are coming from the left speaker and the high notes from the right speaker. The sound is from the hammer strikes and the sound box resonating. I do not really get the sense of a left hand and right hand except from the notes being presented.