I think the first electronic model for Kenmore was a '78 model also. The '79 lineup had two electronic machines, one less feature-filled under the Lady K (no triple dispenser and the standard woodgrain panel top), then the '80 line had the linear control panel as pictured here in Ben and Kenny's machines. I am fairly sure that the last issue of the electronic BD machines was the '82 model, which was in production for several years.
The reliability issues as mentioned above must have been fairly significant, as most models, if they have the longevity of a couple years of production, only got revised a couple times (sometimes a pump or a timer would be changed, which slightly altered the machine's model number but not it's overall appearance), but the final electronic model had something like 6 or 7 revisions, including two completely different processor boards.