The Hostess gowns of the 1970's can be equated to the "Shabbos robe" that used to be and still is cultivated by many a baalas habayis. Often made from polyester, and so unfriendly around stoves, it was ideal for pre-cooked Shabbos meals.
When googling "Shabbos robe," the screen screams with results. It is still with us, it seems.
The article was chronicling the debate of the modern hostess; for the non-Jewish world, the hostess gown is no longer an option. Some want to dress up more, others less.
As a hostess, it seems, there is no wrong way to dress. So be comfy when serving chicken soup.