My architecture wife said houses today are designed (in the US) to last at least 50 years. However I seriously have my doubts that a house could make it that long without some major renovations/overhauls along the way, given that they're essentially built as plywood sheets, stapled to wood planks, protected by plastic siding, and covered with a tar sheet roof down here where I live. I wish the developers invested more into the longevity of a house instead of pinching every penny they can.
US houses can easily last 100+ years. Once they're enclosed, basic maintenance and rare exterior repair/replace gets you a century, unless a natural disaster hits or a freak accident (major fire). With metal roofing becoming common, that removes having to replace the roof except every ~40 years.
You can find plenty of poorly constructed 100+ year old homes in the US, with original innards put together every which way in a shoddy fashion before there were building codes and standardization of construction. And yet there they are, still going with basic maintenance.
I live in Denver. Houses last way longer than 50 years here. Old houses here are quite desirable due to many of these neighborhoods proximity to downtown. The last two houses I rented were from the 1929 and 1943. They were in great shape. They were not the "old house" on the block either, both neighborhoods dated to that era.
Of course they have had several roofs in that time, but roofs don't last much longer than 15-20 years here due to hail. Siding has a limited life, but Hardie Plank which most new builds I see around here has a very long life. Brick will last basically forever along with plaster walls and hard wood floors. The foundation, framing, and plywood basically last forever if you keep it dry.