Earlier quoted context omitted.
This is exactly what I am talking about. You are overestimating how important it is. The code is there and (presumably) in source control. It really isn't that difficult for someone to get the source, compile it and fire up the debugger and carry on where the previous person left off.
And I'm saying that if you have only, or mainly, worked at projects where all information (including about failed historical approaches and why they failed) is encoded in the source code, you have been very lucky to the point where I have a hard time imagining that to be true. There is so much implicit knowledge that goes into the finals source artifact that is not spelled out.
I had an interview at a this week for my next contract where they made redundant most of their employees as the business decided to just go with turnkey applications.
They will get someone like me in for 3 to 6 months to do application maintenance on anything they can't replace. This will be stuff like implementing stuff from penetration-testing, upgrading the applications and documenting missing bits and pieces and letting the business know what needs doing and where.
I don't need a pension being paid, no HR overhead (they can just ask me to leave whenever pretty much). I will be able to gleen enough from the business and their IT to piece the bits together. This is literally my bread and butter.