MonkeyGod Enterprise releases "Frost and Fur"
WotC is releasing "Frostburn."
Mongoose releases "Complete *Race* Books"
WotC is releasing "Races of Stone," supposedly the first in a series of race books.
Goodman and FFG both release books on arial combat.
WotC includes airships in Eberron.
Mongoose, Sword & Sorcery, and a bunch of other folk release guides to the various classes.
WotC releases "Complete Warrior" and "Complete Divine," with two more to follow.
It's not Gygax, and it's not a conspiracy. It's the fact that D20 companies and WotC both want to print books that they think will sell, and sometimes the concepts overlap.