what if we... more?
My guess is that there are a lot of doers, they just aren't posting much because they are busy or want to keep their professional persona a blank slate. I've run into lots of high-octane lurkers in person, but most of them don't have twitter accounts.
If such a person is reading this, don't go posting a ton and tanking your productivity, but consider sending people brief content questions or thank-yous for impactful things? Responses are likely and it's usually worth it a thousand times over for both people :)
Hmmmmm! Is it possible that you have this impression because the same places that are easy to translate quippy insights -- like Twitter -- are particularly bad places to showcase long-term projects? Perhaps the insight IS being used but that part just isn't being communicated?
For example, how do you COMMUNICATE the work you've done on self-therapy... on Twitter? That seems to come off best in a live conversation with someone else, where you can actively sense how someone thinks and responds to you in real time, including facial expressions, body language, etc. To me anyway!