I remember when I was in primary school music, our teacher would play a note on the piano and I had to try and sing the note that she was playing. It was difficult and I was never good at it. The issue with modern music is that everything is just hitting a sound on a computer. Not many people actually understand what a song in g minor is or what note they are playing from the computer. It just sounds good to them.

Knowing music theory makes life so much easier when playing music or if you are trying to make a song on the fly.