Maybe this is my neuro-diversity showing, but my personal experience WILDLY disagrees with that statement.
Your problem is more likely that you value trivia knowledge rather than forgetting important things. Trivia is not important.
Then there's the fact that the keeping of the wiki itself is something I use for rubber ducking and the Feynmann technique.
And since when can't people do things because they like it? Why does everything need to be productive? That sounds depressing to me.
That's the PARA method in a nutshell
https://fortelabs.co/blog/para/
I use this, very helpful, the prioritization piece is by far the most important, if you don't need it now but think you might later, just throw a note with a link in the archive with a couple of tags.
This has additional benefits for efficiency, (DRY) and also usually gives you a result which is generally easier to share with the public, if for example your project file is too personal or too deep for easy reading all by itself.
But there is no reason to re-document. It takes time and doesn't give anything for the project. I typically just have a "meta" folder within a project and any related pdf/video/html I stumble upon goes into that folder. I wouldn't care if a few projects share the same file.
In this case DRY also, in my opinion, only gets in the way. Say you abstract the knowledge to a separate system and start referencing it from your projects. What this does is it freezes the knowledge organization within your system. You cannot relabel things or move them around, because the links from projects to your knowledge base will get broken. This would only add unnecessary complexity and inter-dependance. DRY is one of those things I started looking at differently some time ago. Repeating yourself, in certain cases, can be faster, simpler and more maintainable.
I can also tell some of this is getting into specific case territory. :-) For example, sure, I might not bother referencing a simple component. But that's more like "just Google it" territory. No depth. I have lots of master frameworks that are very deep that I'd never want to repeat. DRY is a life saver there. Those files are also more likely to stay put...
For your moving links scenario, I use search alongside my organization hierarchy and the links double as search prompts. So that's not a problem. I think this is another case where the specifics matter.
For me - a better alternative is to only seek and store knowledge about things you are currently working on, and organise it by project. And if you read something that is actionable - do it and forget about it. Ideas are also fine, but if you have more than 3 then it can be a sign of procrastination.