This is only partly true, historically before private equity was a thing grocery was always a razor thin margin business that operated on volume. PE just made it worse.

My in-laws had a family grocery store back in the 60s and 70s. Privately owned and operated, no way they'd have been paying any attention to security concerns like this.

Their only chance would have been if appliance companies wouldn't be dumb enough to put a simple refrigerator on the public internet in the first place.