Thoughts- Share or not?

There are many drafts that haven't ever seen the light of the world. Not because, they're still draft but, a conscious choice was made to not share. Unfortunately, such conscious choices on various drafts were made and I never bothered to share it with anyone.

Leonardo was way advanced than his contemporaries are but, he never published his works. He never shared half of what he was working on.

I do not know how the world would have changed if only Leonardo had made efforts to share his thoughts. 

How many civilizations have missed the opportunity to change as their people didn't share their works?