And the guys who have it are the "10x devs" in that joint.
>Or they find it "boring".
Or, it doesn't count much towards your annual performance review so then why bother if you have enough stuff on your plate that does count towards your performance review.
When was the last time someone got promoted because they write really, really good internal documentation?
Let's face it, most web facing SW nowadays is like fast-food. Investing tons of time in writing quality documentation would by like a triple Michelin star chef writing a 20 page article about a doner kebab.