Why did most of the dudes in the ads in vintage 1970's Playboy magazines sport porn moustaches, piss colored sunglasses, and resemble a swarthy combination of The Marlboro Man, Franco Nero, and Sam Elliott all rolled into one?
Why not, say, the 70's Marty Balsam in the cockpit complete with comb over and mutton chop sideburns?
if I may answer that- for the same reason people will get up during end credits more likely if there is instrumental music being played then a song. the same reason that if you ask the average viewer what did you think of the music in film, unless someone was singing, they will say WHAT MUSIC?. no respect , no respect.