With the world of work changing so much over the last 20 years (and continuing to evolve rapidly), there is now a common attitude that the past is irrelevant and has nothing to teach us. There is often little knowledge of, or interest in, what has come before; eyes are fixed only on the future. Those who previously worked in the industry, or comparable industries, are thought of as being past it, if they're even thought of at all.
This attitude means that a vast resource of wisdom and experience is going to waste. For while processes and technologies may change, the basic principles of business practice and human interaction (e.g. negotiation, persuasion, collaboration, leadership) do not. There are valuable lessons to be learned from our predecessors; we are much the poorer for not tapping into their knowledge and stories from their careers.
Companies should invite former employees - particularly retired ones - to return and talk to staff about the most valuable lessons they learned during their career, and the most important advice they would pass on today. These speakers would want to take part, as they would feel their experience and knowledge was still valued. And current staff would not only learn lessons and gain insight; they would feel their work is part of a bigger history. I do not know of any company currently doing this.
How would you stage or advertise your hack?
Very simply, staff would be invited to the talk from the former employee using internal comms - a simple email would do the job, but internal posters could also be used. A lunchtime talk (with some food thrown in!) would probably attract the biggest attendance, though if the person giving the talk was a particularly senior and well-known figure, an evening event could still do well. If the talk is filmed and put on the company's intranet, this could be used to generate interest in further talks of this kind - as well as being a lasting resource which employees could continue to access for inspiration in the future.