I had a summer job at NASA in 1969, during the Apollo landings. Sorry about the acronym, it means Lunar Expeditionary Module, the little machine that actually landed on the Moon. I used NASA tech as an example of lost technology, since President Nixon made the decision to shut down the Apollo program in the summer of 1970.
There are plenty of blueprints still around, but tech projects are far more complex than blueprints and circuit schematics. The real, detailed, knowledge is in the minds of the technology group members. When a project is terminated and the group is dispersed, much knowledge is lost forever, and it has to be re-created from scratch if the project is re-animated. "The Project" can be anything from the vast Apollo program to something as simple as a power amplifier.
The folks in the "front office" are the CEO, several marketers/salesmen, and the folks in accounting who juggle the books, paying the creditors in the right order and keeping the Tax Man happy. They are not technology people; they work in the back, along with the assembly staff.
Surprisingly, even though a hifi company may have several marketers on staff, they may not have a full time designer/engineer. The designer/engineers are often "guns for hire" who work at several different companies without credit or recognition. They even sign NDA’s (non-disclosure agreements) so their identities are hidden.
Many high-profile hifi companies, to some extent, are a "false front" and largely a PR operation. The people in back who design, prototype, build, and repair the gear are anonymous and often fired at whim, or if business falls off a little.
You can see why this puts the "brand name" in a different light. The real engineers are an anonymous cast of rotating designers, hidden behind unbreakable NDA’s, while the folks who stay-the-same are the CEO and the PR team. They provide the brand identity, but it is really a mirage in terms what’s inside the product. So if the "front office" folks go away, nothing is left except a memory in the minds of the customers. In legal terms, that memory is called "Goodwill" and has a monetary value.