Well, of course it is easy to push discussions of this type way beyond any level of practical application. But once we get there, we still have a bunch of clarifying to do to make sure we are talking about the same thing. The definition of traditional music that works best for me is centered around the actual music - the melody and the lyrics. With this definition it doesn't much matter what instruments are used, how the music is arranged, where or when it is from, or how it is used. The music is defined by actual musical considerations, not social or historical ones.
Traditional melodies sound very different than composed melodies.
There are, of course, lots of people writing new tunes in traditional styles. These are also a vital and necessary part of traditional music. There are composed songs that don't sound traditional at all but probably will in after getting played continuously for a couple of hundred years. These are also part of the tradition, but we have no way of recognizing them until they get there. They haven't been through the folk processor yet.