"When did we start asking ourselves questions like 'am I still Company X's target audience?' instead of questions like 'Do I like this product and does it suit my needs?'".
For myself, it was when I started realizing the following:
a) I liked products from numerous third party companies including Adamant, Green Ronin, and RPGObjects;
b) I considered only 17 WOTC 3e DND supplements to be worth purchasing;
- 8 of them without requiring a discount (Unearthed Arcana, MM2, Fiend Folio, Book of Vile Darkness, Fiendish Codex I, Lords of Madness, Heroes of Horror, Stormwrack)
- and another 9 (Arms and Equipment Guide, Complete Arcane, Complete Warrior, Complete Mage, PHB2, DMG2, Dragonomicon, Sandstorm, Savage Species) provided that I could buy them at a minimum of 75-80% off the cover price. And, even then, less than 50% of the material in these products would be used. To date, I still don't own any of these, because other books have priority.
(Note: To be fair, I haven't seen Cityscape or Ghostwalk so they might fall into one of the above categories);
c) I didn't like d20 Star Wars (with the exception of its treatment of the force) or Star Wars:SE with its per encounter abiities, over consolidated skill lists, and removal of skill points ( a shame, because I like some of the other elements of SE like talent trees and the condition track); and
d) I disliked WOTC's d20 Modern supplements (to be fair, I found d20 Future to be mediocre. Also, I haven't seen d20 Apocalypse or d20 Cyberscape so perhaps they are worth buying);