So, while the D20 OGL SRD (http://www.wizards.com/default.asp?x=d20/article/srdarchive) this led to:
"When it was published in 2000 along with the 3rd edition of the rules, the OGL sparked unprecedented growth in the RPG industry. The OGL made it so easy to use the rules conventions of D&D like hit points, spells and monsters that hundreds of products - the official signifier of D&D-compatible materials created using the OGL - emblazoned on them made their way to game store shelves."
-Escapist (http://www.escapistmagazine.com/articles/view/features/9292-The-Ghosts-of-D-D-Past.2)
Why did WotC not do the same with D20 4.0? After all, they are suffering right now, and I am believing its a result of ending the continued use of an OGL SRD with the newest editions!
The OSR is on the rise, along with other digital media creating a paradigm shift in the world of traditional gaming:
"Changes in how people buy RPGs and the freedom of the OGL combined to make the Old School Renaissance grow across the internet. The rise of digital distribution of PDFs through marketplaces like DriveThruRPG.com have allowed designers to make money selling their work with less overhead. The costs of printing books has also decreased, especially print-on-demand services that allow smaller print runs, so it's easier than ever for amateur designers to publish something gamers can bring to the table and use with any of D&D's older editions or retro-clones."
-Escapist (http://www.escapistmagazine.com/articles/view/features/9293-The-State-of-D-D-Present.3)
Right now the world of games is going through a paradigm shift. Board games are still going strong in many respects, but also deal with similar limitations. What we all enjoy though is an increase in development budget, but we pay for it. Fantasy Flight Games makes beautiful board games with high quality laminated cardboard components and beautifully sculpted plastic pieces that used to only be the realm of pewter. However, its around $70 to $150 for these games as opposed to the $20 to $50 the same game concept years ago used to cost (part of that is indeed inflation). RPGs however, are contracting sharply.
Steve Jackson Games publishes most GURPS supplements electronically, and spends the majority of the printing budget on the biggest cash cow of the company, Munchkin (I enjoy Munchkin myself...). Other game companies are starting to publish more and more through DriveThru RPG and RPG Now. Holdouts like WotC are suffering (that 4th Ed. wasn't so well received...).
As a result, we've seen the OSR take the OGL and thrive online. Be it free rules, or low cost .pdf and print on demand, indie development seems to be rising. Sales wise its harder to track... Number of downloads would be an interesting figure to find out between the biggest names I've seen from OSRIC, Swords and Wizardry, and Basic Fantasy; along with sales of Labyrinth Lords and others.
Frankly, I think we need to embrace the OSR. Where D&D 3.0, 3.5, 3.75, and 4.0 to varying degrees seemed to have failed is competing with computers. Where the OSR takes 3.5 and strips the SRD down to the basics, and gives the GM a lot of story telling and rules adjudication power, it seems to thrive. Volumes of rules, be it the many GURPS books I've enjoyed over the years, or some of the 3.5 books a friend gave me, only serve to slow down games. Most of the gruntwork is best done by a computer, and then you wonder why you want to sit at the dinner table with a group of friends (unless you have a good GM who will throw the rules out some of the time anyway, which frankly is how the rules recommend being played anyway...).
That, and I'm a sucker for anything of quality to come out of Open Source. I have little money to spend and waste on games anymore. If the rules are free, I'll take em and use them when I feel like dungeon delving. I'll use my "Descent: Journeys into the Darkness" game board and figures with BFRPG or Microlite 20... Why the hell not? To top it off, I like to draw pictures and get my art out there.
So, anyone in the OSR development world working a real job and designing games on the weekend is more than welcome to bug me about drawing up some creature sometime. So long as the deadline is flexible... I'll embrace OSR and OGL and use my FOSS image editing software (www.gimp.org and www.inkscape.org) and have some fun with you, for free.