The town I grew up in...
Elk Grove Village Illinois had about 400+ homes built between 1961 and 1970 with Waste King appliances. The smaller homes featured a built in cooktop and wall oven, and a disposal, and the larger models added a DW.
I had a few friends who lived in these houses, from what I remember the DW was the first to go, just didn't seem to last that long. On the other hand, the disposals lasted forever!