Well, considering the amount of work Mel Gibson gets these days (more or less zero), this does factor in a bit. I also gather that studios hire actors for reasons beyond their acting skill quite often. Consider also how many actresses fall off the face of the earth when they hit a certain age. Where's Mira Sorvino? Halle Berry? Jennifer Garner? Jessica Alba? Did they suddenly forget how to audition?
Considering all the TV shows where the actors are cast by the 8x10 glossies, it might even be the default to undervalue auditions.
