They might have replaced it because they were tired of avocado green. Different people see colors differently. Maybe something needed repair and that was the trigger to just get new stuff. Or maybe they had never liked the layout of the kitchen and remodeled or remodeled to make the house more attractive and up to date looking for selling it. Nothing dates a house like the kitchen and bathrooms. Maybe the original owners sold the place and the new owners redid the kitchen with "professional look" appliances that probably won't last as long as these and, if they went with gas cooking, will need more service for those fragile electric ignition systems.
Whatever the reason, they got many decades of use out of these and, with care, someone who likes or can stand avocado can get many more years of service out of at least the cooking appliances if they are working now.