Why does light not break the sound barrier?

1).  The sound "barrier" is a shock wave that builds up in whatever material the object is traveling through.  The object has to push air out of the way to let it through, but the air can't move out of the way any faster than the speed of sound.
Light isn't traveling through any material, and it doesn't need to push air out of the way to let it through.

2).  The sound "barrier" shock wave forms as the moving object builds up closer and closer to the speed of sound.  Light never travels slower than the speed of sound, so it never builds up closer and closer to the speed of sound.