Yes, I agree. In the DMG, there is only a few (vague) sentences on how to award good roleplaying, yet in the PHB there is 27 pages on Combat alone.
I would have to say D&D is becoming more of a 'war-game' instead of a 'roleplaying game'.
(The mini's/battle mat argument can enter here...)
Second, $$$. I know this is not only a WotC issue... I remember fondly the days of getting D&D (1ed) adventures. Tons of them! However, some market bean-counter realized that at a table of 5 gamers, only 1 person (the DM) would buy the module. So along came the $-factor where they pumped out books that everyone at the table could purchase (handbooks, etc).
Now we have 1,000's of rules/manuals but no adventures to play in...
(It seems they were waiting for other d20 companies to put adventures out - - but they also took their direction from WotC and produced splat-books as well...).
To me (my opinion only) the industry (WotC leading the way) focuses on "what books will sell the most", not necessarialy what is good for the GAME itself.