Have you ever wondered why so many large chain stores have two sets of doors? No, it is not just to store shopping carts.
Where I live, any home that is around 100 years old (that hasn't seen any renovations) will very likely have two front doors. Putting it simply, you open one door, step into a small space, and there will be another door in front of you.
(Image Sources: Image 1 | Image 2)
The space goes by many names, including: arctic entry, mud room, breeze room, vestibule, airlock, foyer, and more. For sake of simplicity, I am going to call them "entry vestibules."
Entry vestibules create a buffer between the outside and the inside of the building, preventing drafts. This can help greatly with temperature regulation in both the winter cold and summer heat. I can't find number details on energy saving, but the fact that large chains still build them may hint of their importance for money-saving.
In homes, this space also typically serves as the mud room ( a place for shoes and jackets).
In the name of "first impressions," and open concept designs, vestibules are often the first thing to go during renovations, and I think that's a real shame.
I grew up in a rural/small town area where mud rooms are still highly valued to this day. Even small houses will occasionally have mud rooms.
It won't be very long. The house bubble will settle over the rural Midwest. It's already begun. 3br 1bath 1k sq ft are already north of 300k. The one dollar tree in town won't support it. Trailer parks are already getting bought up by equity. We need guillotineabules, not vestibules.
I mean I agree with you, but in my small Midwestern town, it's cheaper and easier house maintenance to have a mud room instead of constantly cleaning the floor in front of the door. I think houses in the cities will see them disappear, but not in places where the towns are ~300 to 50k people. It might become hard to find in small houses in the Midwest, but it will still be there in most mid sized houses