I'd say it is culture, not code. Twenty years ago, chains like California Pizza Kitchen were archtypical as noisier than average with lots of metal, glass, and other hard surfaces. It was already a cliche by then, but it wasn't the only style successfully operating.

What I've seen over the decades is those others going out of business and being replaced by either the glossy, clean style or the unfinished industrial style. Nobody is using soft materials which remind too much of our fathers' or grandfathers' banquet halls and family restaurants.