I have lived in two smaller tract-type houses similar to the Laurean's in my life - one had the WD in the garage and one in the hallway of the house. Since the garage isn't usually heated, often the WD being there has to do with the climate. In places without basements like TX, FL, Coastal NC, SC, LA, GA, etc the garage is a common place for the WD. But in places like OK, MO, KS - it gets much colder and the WD kinda has to be inside the house or the garage heated in winter to avoid frozen pipes. As far as doors - ONE house had the access to the backyard ONLY thru the garage, the other had access from the house directly to the patio and NO access from the garage to the backyard.
And NEWER houses, at least here in temperate Texas, and in my BIL's region in Wilmington, NC have MANY doors to the back yard. BIL's custom-built house in NC has like 5 or 6 doors to the backyard - including one door he specially requested that opens from the rear of the garage in the "workshop" area to the backyard. Our last house in Dallas had 4 HUGE doors (2 patio doors, 2 french doors) that opened to the backyard/patio - but none from the garage (garage opened onto driveway on an alley) - access to the backyard was from the driveway thru a gate). Our current house has 5 doors to the backyard from the house and again NO door from the garage to the backyard - here you have to go outside and across the driveway and go thru a gate and down another walkway alongside the house to get to the backyard. Both houses you walk thru the utility room (with the WD) to enter the house from the garage.
I never thought about it till now, but I have never lived in a house my WHOLE LIFE that had both a door from the HOUSE to the backyard and one from the GARAGE into the backyard. The only houses I have seen with both a garage-backyard door and house-backyard door were custom-built or a total remodel.
I think a LOT is dependent on the age of the house, and the climate - I have lived in 6 different states though, and in houses from older small and basic, to new, large and upscale. In my experience only remodeled or custom-built houses have BOTH a garage door to the backyard and doors from the HOUSE to the backyard and only houses in warmer climates and houses built in the 50's -70's have the WD connections in the garage. Later - even in warmer climates, the WD is in the house somewhere.
Just My Experience Tho....