No disrespect, but I'd go further and ask, why should the Grills or any part of a Cunard ship be any different from the way I dress for dinner at home? Or the way I dress watching TV in my living room? Why should I ever have to "dress up" anywhere at all. Blue Jeans should be fine at the Oscars, at the Nobel Dinner, and at Royal weddings. Why does the world feel a need to dress up at all? Tradition? Taste? Fun?
Once upon a time, Cunard was all about maintaining those old standards of dress and behavior associated with the Golden age of the great luxury liners. Most of us thought it was fun. We weren't going to win a noble prize, but we could dress up and feel special in the lap of luxury. It's what we came for. I, for one, lament it's demise.