The first picture shows our hall before tear-out. The doors to the right enclosed a broom closet.
The next picture shows the hall after tear-out.
It turns out that the broom closet contained a laundry drain (which you can see at lower right corner) and an outlet midway up the wall. This washer location was most likely the original! Perhaps the dryer was to the left?
Interestingly, we had contemplated putting the laundry in this exact spot but decided it wouldn't have worked.
If we had only known!
Where else has the washer been? After the hall location, it apparently was moved to the basement. It was probably there for many years.
The couple we bought our home from moved the laundry back upstairs into a bedroom they converted into a sort of second bath/laundry.
When we moved in, we put the used washer/dryer we bought back in the basement!
Finally, we ultimately re-worked the bedroom conversion into our master bath/dressing area/laundry.
The spot for our washer/dryer is shown in the third picture, just to the right of the shelves.
We left our old washer/dryer in the basement for extra-large or extra-dirty loads.
Consequently, we will have the best of both worlds!