I think commercial music is what ever the mass society at that particular time seems to embrace, I don't think there is a formula for it, nor should there be. I think having that kind of attitude will only stunt creativity.
Remember there was a time not too long ago when bands like Yes and Emerson, Lake, and Palmer etc achieved much commercial success, I don't believe they had a formula. They took lots of chances.
50 or 60 yrs ago the music of Charlie Parker and the Be-Bop movement was considered commercial music, as well as they music of Duke Ellington and Louie Armstrong.
Mozart and Beethoven where considered commercial musicians in their day.
Be brave, be creative, and move forward. Don't reproduce but compose........just my moto.