I don't think you can beat pen and paper. It's cheap, portable, it's easier to remember what you write vs digital input and it's easy to access. Given that, I think it can be improved.

I've used OneNote before and it's great at organizing note so I've started to take photos of my notes and organizing them in OneNote. In theory, it can OCR them but it's really wishful thinking given my handwriting.

I suspect that my notebooks will outlast my OneNote notes but only time will tell.