If you can hit a keyword and get straight to the point on a particular topic, what's the point of stressing things?
The more you write, sometimes it complicates things without the author even realising it. At the beginning, most of the long text might have meaning, but the more you read it, the more confused you get about what the person is saying.
You are absolutely correct, that is why it's very important to know or be sure of what you are doing or about to post before writing it for others to understand and read meaning to what they post.
So actually it's not by quantity but by quality, we should do things easier for people to read and understand what they are reading and also it can be helpful to most people in the essence that they will learn from it.