There will never be the degree of unity again in the future that there was in the past.
People are losing the ability to communicate with each other, because interests are becoming so technical and specific that to be able to discuss a specialized topic requires it's own specialized jargon. Groups are able to find each other no matter the distance and this speeds the development of specialized languages.
Under the auspices of gaming rests tabletop gaming rests role playing rests our own little corner or niche. There are so few people who play role-playing games, classic gaming is a niche within a niche. It will never again be like it was in the early 80's. Even the very most popular things - something wildly popular like Twilight book series, reach a ridiculously small part of the population. Only 1 in 3 Americans have bought the book, and that is something that approaches the maximum success something can have. (1 in 3 americans if the other 5 billion, 800 million people didn't buy one copy). Numbers much smaller then the church could claim before the reformation, no? It is not a group of people who do one thing - it is many, many different things for many many different people.
So there will be no riches at the end of the rainbow for the creation of content in any medium. Deciding to self publish rpg material is no road to riches. Our hobby, like many others, is so specific as to be unintelligible to many who are even fans. (How many times have you see someone ask what BECMI is? Or the differences between the versions of Dungeons and dargons.?) As I said, this is not restricted to our hobby - every hobby is moving in this direction. I can't even watch football without a guide to explain the spreads, fantasy data, and rule changes - and this is for a popular sport. It's even worse when you talk about people into first person shooters, or indie cinema, or the plethora of musical genres (Cuddlecore? Yacht Rock? Crabcore?). In fact the very issue of work for money is in flux - with movies and music being available free online (leagally, hulu, pandora, anyone?) how will anyone support themselves with creative effort? It is very likely they will not be able to.
So why do it?
That's an easy question to answer. Do it for yourself. Because you will use it, or because you enjoy it, or because you can't not do it. Give it away for free digitally and offer a printed or collectors version at cost or a profit so that those that want to support you can. But mostly do it. Don't worry about what doing it will get you. Think about what doing it gives you. Let the rest take care of itself afterwords.