I love them too - love all dogs! But the Cocker breeders went way overboard on inbreeding - pushing the limits on line breeding as well. It compromised the health of the breed. They lost sight of the purpose of the breed, and instead went for type.
My "little black boy" was adopted from the cocker rescue. He is very needy and clingy. He was around 2 years old when I got him and he doesn't have nearly the smarts, tricks or vocabulary that my other cocker does that was raised from a baby. I understand what you are saying about the breeding practices just from the little guy I adopted, who was rescued from a puppy mill. He's a sweet little guy and he loves his mommy and cries if I leave.
Cockers are an excellent, loyal breed. Labs, too, are among the best breeds, from my own experience.
Actually, what harmed cockers was not inbreeding or linebreeding, it was indiscriminate breeding. When a breed becomes popular people see $$$. There are those out there who just start putting together any 2 examples of a breed because the puppies will sell easily. They don’t research, they don’t breed toward a standard (and all breed standards talk about temperament, not just conformation). They just breed. THIS is what produces large numbers of poorly bred dogs.
Even having said there, there were still nice cockers to be had, but just became the minority.