Before I had ideals of making a game and distributing it for free, out of the goodness of my naive heart, then people will realize how great it is and people will buy it. That was a long long time ago, after growing up, learning business, and several failed attempts I realized that if its free, then people will never know how valuable it is.
I love Open Source. I love Open Office, Ubuntu, GIMP (open source version of Photoshop), Blender (open Source version of 3d max) etc. I really appreciate the value and economics that goes about making these open source materials possible. I also understand how it works enough to never let these things be taken for granted.
It is commonly found in many books about Human behavior (Predictably irrational and in Game Theory) that people judge value irrationally. So even if it is a GREAT product, people will attribute it more for its price than more than what they can observe and what rationally are their needs from the product.
There is great FREE RPG STUFF online, but people would rather buy it than look for it the internet. As this argument (this Trolling) in the SJgames forums can lead one to realize.
Adventures are one of those things you find everyone has, at one point, contributed. You can find them in OLD campaigns, sample encoutners or adventure logs, premade and organized with a bit of polishing needed, and bloggers who specialize personally helping other GMs prep for their game.
Just because its free, there is a great majority who take it for granted and do not see the passion and sense of community that comes into making such things possible.
Never has there been such wealth of free material in the History of RPGs. Hopefully, in the future, in the evolution of ideas and memes we become more organized, more refined, more diverse and grow in ways very few have anticipated. RPGs may never be as popular as other hobbies, but it sure does something other hobbies can't.