Sears became the poster child of horrible customer service in the 1980s and beyond. That is what killed it.
I bought a Sears water heater with my Sears credit card in the early 1990s. Literally ONE MONTH after the manufacturer's warranty expired, the lining became separated from the tank and it had to be replaced. They flatly said the warranty had expired and refused to even give me a partial credit toward a replacement. They were fully within their legal rights to do so.
And I was fully within my legal rights to cut up their credit card and mail the pieces to them, and never again set foot in a Sears store. I told them that if they sell crap, I'm not buying.
The auto repair scandal in the late 80s certainly didn’t help.