In 1947 Heathkit began selling it first kit, a basic oscilloscope for $50. It came with all parts, a manual in English that was a complete assembly plan, step by step instructions, and a theory of operation. It was considerably less expensive than what was available, but it was a basic O-scope. But this opened the door for many electronic kits over the next 40 years. Audio amps, ham radios, test equipment, computers, and even a robot, (Hero 1). I have built many Heathkit products and was part of the assembly of the Hero robot. It cost about $1ooo in the late 80's, and was an extremely complex build with some 20 printed circuit boards. But, the value when finished was much more, as complete robots were in the $2,500 range.
But I believe that the value was not always in the cost savings but in the educational aspect of the kits. Two generations of builders learned "how to" from what was considered the best manuals in the industry. There were competitors like Allied Radio, Lafayette, and even Radio Shack, but they never matched Heath. With the advent of double sided PC boards, surface mount components, and the electronics coming from abroad, Heathkit went out of the kit business in 1992.
And, with the respect that I have for the Heathkit name, I believe that the trend is not toward the kit model. I suspect that there will be partially assembled and fully assembled parts to put together into a functioning device. But, the excitement of building from scratch and checking off the step by step assembly is nearing and end. But, it is nice to see the desire to return...