Comment by bdangubic

the reason this is rare is that no one stays on any one project long enough for this to be a reality anywhere. you know anyone working 15-20 years on the same project? I’ve been on many projects where deep explanatory knowledge existed through and through until the project was initial-code-complete and then people left to do other amazing things leaving project with people with limited knowledge of it. I suspect this is the case for vast majority of software