Don't waste your time looking up the word authenticity on Wikipedia. They are stuck in a debate that I had to listen to 60 years ago when Erich Fromm and David Reisman were the last word. Since then Charles Taylor has moved the debate further along.
My view on authenticity is that it is an emergent function. You don't know what you're authentic qualities are until you explore and fully develop them. That development occurs in an environment that has direct relevance to your authenticity.
Who you are (identity) is not stable nor clearly definable either. Once again it is emergent in an environment. You can be a father, a lover, a liar and a dangerous driver plus hundreds of other things. Your 'youness' emerges in each environment.
So when you combine the issue of who you are with what is authentic about you we have a pretty large set of overlapping circles. Many of which are emergent when you live and explore. Some qualities, like a sense of humor, are in a circle at the center of all the circles.
My interest and concern about authenticity as a pro-commerce issue is that only in a commercial environment can someone find their authenticity.
The world of commerce gives each of us a vast array of skills and talents to explore and develop. A few of which can act as our rightlivelihood.
In a non-commercial society, such as Cuba, Saudi Arabia or North Korea we become whatever the society demands. That has little or nothing to do with our authenticity or who we are.
The absence of a commercial world is what dooms people to a stilted ... zombie like existence. This is ultimately my strongest argument for a pro commerce position.
I have enjoyed a full life, I have explored my personal attributes as fully as possible, throughout my life and it is the commercial world that made that possible.