My only-mostly-joking answer is that you can go work for a typical Silicon Valley style technology company, and stay around for two or three four-year vesting periods. Most of them have Google-influenced design doc processes, and few if any have a process for documenting what actually got built, much less what it eventually turned into.

One of my hobbies is feeling dumb for not understanding something, being willing to ask, realizing _nobody_ knows the big picture, and trying to document it.

tbh though I have also occasionally fantasized about finding a job that was _only_ software archeology.