Earlier quoted context omitted.
Is it possibly not a management problem at the core? I mean, I know exactly what you mean about suits like to ignore the future, but I've worked with a few 'wizards' who, once they've got the job under their belt, use it to keep other people out. They'll not comment, help, document or whatever, and once they're doing that, they are uncontrollable. They can't be sacked because they're the only ones keeping the system…
well if you have 3 guys that are the wizards that can't be sacked, hire 3 contractors for a year long project to document things sufficiently that these guys become more sackable. Contractors of course have to be highly experienced as well, and well-remunerated, so maybe management doesn't want to go down that expensive avenue, which means it's a management problem. Not to mention the years where they did not comment…
Don't forget to also sack the management that looked the other way for years while this situation got where it is.
The zero asshole rule is non-negotiable.