I would like to liken raw photo as a naked lady and processing it with PS as putting on clothes and makeup.
Sure, if the naked lady is a roaring beauty, then the pic itself is well taken. But adding clothes and makeup will definitely enhance the beauty even more. In PS terms, it could be adding border, using a certain colour tone to create a certain mood, sharpening, adding vignetting etc....
One forumer above mentioned that a singer cannot be considered a good singer if the song was digitally enhanced. I wld like to think of it another way..... i.e. raw photo = singer singing without mike and music/band. PS = adding mike and music/band.
In the above scenarios ... processing (whether is it PS, makeup, clothes, band etc) makes the end product more professional.
Thats my two cents