"Macho" Commercials

Why is it that in most commercials that have to do with buying new floors or windows, there's this couple formed of a 40-ish beautiful woman and a 60-ish man who looks as if he were made of money? She just sits there, smiling and nodding, while talks to the salesman and looks like he's going to take out his loaded wallet any minute.
I could write 10 pages on this subject, so I'll just stop here.