[kamaal]

Brain was designed to process information(mostly), not to store mass quantities of information. I mean it's more like a RAM/Cache than Amazon Glacier.

If you don't put knowledge into practice it all goes quickly.

[kiba]

We can store massive quantities of information if we bother to hack our brain/learning process.

[beckingz]

Yes, but it has to be maintained.

The issue is that we have no incentive to remember information that is 'useless'. So the brain, being efficient, forgets it.