The answer lies in several places. First, he describes his voice as traditional, or classical pop, and by that he means he sings in the style of the great pop singers of the 30’s through 50’s Listen to the great big band singers of the war era and you will quickly hear a lot of, and great vibrato. That was the standard sound of popular singers. Over the years, singers drifted away from that sound, to the point of using almost none at all. It is interesting to note that the vast majority of “stars” today couldn’t get a record contract if they lived in the forties! Josh has a great classical pop sound of the last generation, and a lot of folks are waking up to the fact that it was incredibly beautiful. His audience make up reflects this.
It’s not that Josh uses too much vibrato, it is that we are not use to hearing it today, unless you listen to opera of theater music. Think of all of the great musicals that you have heard in your life. They are all sung with a lot more vibrato. Josh is a very smart singer, he sings songs that play into his strengths. and, he is just unique, he defies modern classification. In what he does, he stands alone. There are other great voices that are close to him in talent, like Michael Buble, but no one else sings in so many genres, in so many languages, with the amount of success that Josh has. He is a true classic, a popular classic. Let there be vibrato!