Mark
CreativeMountainGames.com
Hi Aaron! 
I largely agree with what you say though my own impression of the numbers might be a bit different. It's worthwhile for me to further clarify my own reasoning for agreeing with you, as well.
Conventional wisdom is that 20% of the market is DMs but that they make, or influence, 80% of the purchases. What they will allow in campaigns largely guides the marketing and product development of Third Party Publishers.
Additional purchases made by players can also include Players' Guides to (Campaign Setting), anything with crunchy bits geared toward player characters, and (as you mention) anything that helps a player transition into the role of DM.
It might be closer to 10% or lower, from what I understand (perhaps 20% for electronic publishers).
"We do the work, so you can play!" is the motto at Creative Mountain Games for that reason, among others. I agree completely that assisting DMs to run games is an excellent way to target the largest portion of the market, and that a healthy business attittude should be one that reaches out to the player population and helps ease conversion to the DM chair. It has a number of residual affects that are good not only for an individual company's sales, but also for the RPG industry as a whole. (The more DMs, the more people that can play. With more chairs at the table, the more that can be filled from outside of the current player ranks, thus increasing the market, etc.) This is a good long-term attittude for any RPG producer that serves to ensure their logevity.
It's worth further addressing that there are a number of reasons why the market plateaus around that 10%, perhaps chief among them being the hurdle from "Official" products to "Third Party Publisher" products. It is unlikely that Third Party Publisher advertising budgets will allow for that barrier to directly be broken in a significant way, which is why I further agree with what you suggest as being a great approach. The more "new" DMs that come to the table already accepting of Third Party Publisher products, the easier it is to spread the message that those products can be very useful to the games being played.
The toughest single thing for any new company is weathering the lean times from inception through becoming a self-sustaining entity. It is my hope that consumers will give companies like Creative Mountain Games the ability to get through the tough periods and eventually grow into that "middle tier" where it is possible to further produce materials that help to grow the hobby as a whole. To that end Creative Mountain Games does everything it can to support the community (assisting great sites like EN World and the people who comprise the community, helping with conventions and gamedays, producing materials to make playing less of a chore, etc.), and hopefully garner the respect and support of the of the community in return, as has been the case thus far. Thanks to everyone who appreciates CMG products and services. The continued success of CMG is a good example of consumer purchases directly effecting how the hobby and market grows!

I largely agree with what you say though my own impression of the numbers might be a bit different. It's worthwhile for me to further clarify my own reasoning for agreeing with you, as well.
jester47 said:Here is the rational behind my challenge:
In the d20 market your customer base is the DM. There is nothing else really to sell to.
Conventional wisdom is that 20% of the market is DMs but that they make, or influence, 80% of the purchases. What they will allow in campaigns largely guides the marketing and product development of Third Party Publishers.
jester47 said:Players by the minimum of what they need. That is ussually the PHB. So you can't look at your market as everyone who plays d20, it is in reality those who run the games.
Additional purchases made by players can also include Players' Guides to (Campaign Setting), anything with crunchy bits geared toward player characters, and (as you mention) anything that helps a player transition into the role of DM.
jester47 said:The population of this market is small generally being generous we would say 20% of the market for the PHB.
It might be closer to 10% or lower, from what I understand (perhaps 20% for electronic publishers).
jester47 said:If we make tools that make DM preparation time similar to character creation time, you will grow the DM population, in fact it may very well become one and the same. Such an event would equate to more sales in the d20 market.
"We do the work, so you can play!" is the motto at Creative Mountain Games for that reason, among others. I agree completely that assisting DMs to run games is an excellent way to target the largest portion of the market, and that a healthy business attittude should be one that reaches out to the player population and helps ease conversion to the DM chair. It has a number of residual affects that are good not only for an individual company's sales, but also for the RPG industry as a whole. (The more DMs, the more people that can play. With more chairs at the table, the more that can be filled from outside of the current player ranks, thus increasing the market, etc.) This is a good long-term attittude for any RPG producer that serves to ensure their logevity.
It's worth further addressing that there are a number of reasons why the market plateaus around that 10%, perhaps chief among them being the hurdle from "Official" products to "Third Party Publisher" products. It is unlikely that Third Party Publisher advertising budgets will allow for that barrier to directly be broken in a significant way, which is why I further agree with what you suggest as being a great approach. The more "new" DMs that come to the table already accepting of Third Party Publisher products, the easier it is to spread the message that those products can be very useful to the games being played.
The toughest single thing for any new company is weathering the lean times from inception through becoming a self-sustaining entity. It is my hope that consumers will give companies like Creative Mountain Games the ability to get through the tough periods and eventually grow into that "middle tier" where it is possible to further produce materials that help to grow the hobby as a whole. To that end Creative Mountain Games does everything it can to support the community (assisting great sites like EN World and the people who comprise the community, helping with conventions and gamedays, producing materials to make playing less of a chore, etc.), and hopefully garner the respect and support of the of the community in return, as has been the case thus far. Thanks to everyone who appreciates CMG products and services. The continued success of CMG is a good example of consumer purchases directly effecting how the hobby and market grows!
