Richard, didn't miss it. Just disagree.

The director, whether he wears one hat or three or many, greatly determines the final product. Same as a conductor. Have you ever played in an orchestra? You'd be surprised how one individual, the conductor, can affect the performances of so many.

I see it this way...
Movie making is not a Democracy, it can be more or less democratic, but at the end, "USUALLY" if something is wrong on a movie it´s going to be the Directors fault.

If something is not good, No one is going to blame the First Assistant Director.. or the Gaffer... (maybe the producer)...

So if the director carries the final responsability, I think he/she can put "A film by" if wanted. Allthough some times it does sound a bit out of place.

ACtually it could be considered an act of courage... (ot stupidity, considering some movies out there).