That's not a shortcoming, contrary to what some in the development community believe. I understand that Open Source Developers are usually volunteers. Not a problem. Their efforts are commendable and much appreciated. You need to be able to support what you are developing, if you are going to release it to the general public.
Developers already have a great skill, and that is programming.
The skill they need to develop is documentation for the masses. It just needs to be well-explained so that users can understand it. After all, as much as some developers hate to admit it, attracting users is what makes a product successful.