I know that just twenty or thirty years ago, attending a similar event, every man would have been wearing a collar and tie. Not now. Many of these were senior architects and developers and historians and City staff, but only a very small percentage had neck wear.
This kind of casualness seems to be standard now, at least here in Vancouver. Good thing, too, as I couldn’t find a tie to wear and so just skipped it.
Thank goodness I didn’t inherit a tie shop!