I don't know, guys. Maybe it's because I come from a music background (where it is sometimes a little more obvious when someone just doesn't "have it" no matter how much analysis, practice and effort they put it), but while it is perhaps slightly too strongly worded to say not everyone is an artist, it's not far off. Certainly we can at least apply it to individual branches - ie not everyone is a photographer. Someone might love photography, but ultimately not be much of a photographer no matter how hard he/she bangs his/her head against the wall (or doesn't).
I come from a music background too, and I think it's wrong in that context too. IMHO, this line of thinking confuses "being an artist/musician" with "being a *really* *good* artist/musician", and I think it's actually a harmful confusion that prevents a lot of people from finding things that they and an artform can do for (or to) each other.
San Diego, CA, USA
The lady of the house has to be a pretty swell sort of person to put up with the annoyance of a photographer.
-The Little Technical Library, _Developing, Printing, And Enlarging_