Just my little brush with a few Hollywood types, but I can tell you virtually all had a tendancy toward the engraving embellished as opposed to plain. Some more tasteless than others. Some very tasteful preference in their choice of engravings.
I have one friend that has had a few unengraved guns but with very expensive wood and checkering on high quality guns. He could afford most any engraving he desired, but opted for plain. So, I suppose it isn't always a matter of affordability. But, I'll be willing to bet it is about affordability more often than not.
BTW, y'all should go over to the Fox forum and look at Dewey's custom sideplated Fox with the engraving on it. Very tasteful, IMO. I think it was layed out to accentuate the sideplate job at it's best.
I will say that I believe an engraved gun with pretty wood attracts people to it in a used gun rack first before a plain gun of equal quality. The engraving and wood gets the once over, then the practical eval of the rest of the gun (and pricetag) takes place. 'seen it, done it myself. 'fact of nature.