It's always the same problem: The work generated by doing documentation, including the possible need for specialized talent, is quite directly perceivable. The work generated by the absence of documentation is more under the radar and disguised as “cost of doing business”, which makes it harder to convince the anti-documentation crowd. Not to mention the “job security” aspect of everything being in the heads of the ICs.
In other words, it's a principal-agent problem. The ICs (agents) tasked with creating documentation see it as extra work with no immediate payoff for them, and indeed even some long term downsides; the org (principal) bears the hidden costs of its absence - inefficiency, delays, trouble when Mr Magic Touch switches jobs. There's nothing special in kind about this, it happens in all industries.
The fix? Stop leaving it optional. Tie documentation to performance reviews, bake it into deliverables, reward teams for knowledge-sharing. If you can’t convince them with logic, align incentives so ICs can’t ignore it. It's either that, or accept that you believe ICs have better things to do with their time. But make a conscious choice either way, I'm begging you!
Forced documentation by ICs could be poorly written, leave things out or quickly sync out of date. I think there should be a dedicated team tasked with managing this documentation.
So long as you have the budget to hire for that, the world is your oyster. Alternatively you could take the risk and pass the savings on to the consumer - it's all up to you, my friend.
