While the markets may overlap, they're not identical. GW's IPs are more than just the tabletop games, and various people like various aspects. For instance, I never really got along with the later editions of the game and stopped playing, but the lore and expanded universe is pretty brilliant and hooks just as many people.
Besides, simply because it's set in the same universe, it doesn't mean all (or even the lion's share) of the money made from the game will go to GW. Game devs, especially for evolving worlds like those in MMOs, have to do a ridiculous amount of work and frequently expand content. That's not free by any stretch, to say nothing of server costs and other ongoing events.
So in short? No, you don't 'pay enough' if you're only buying the models if you're also wanting to play an MMO.
WoRLoKKeD. You misunderstand my gripe/point. No, I am not ONLY buying models. I also have no played consistantly since 4th ed but the 40K lore is brilliant and it has hooked me since I was a little kid. Not only do I collect the models. I also have a fairly large collection of the books (paperback/digital), artbooks, and yes, videogames. I have no problem spending $$$$$$ on anything from GW if it grabs my interest.
My gripe is MMO's. When one pays $500-$1500 dollars for a gaming system then has to go out and spend another $60/game, that enough for ME. If you enjoy paying as you play. Have at it.
If Eternal Crusade was something like Diablo (as far as the "World" you play in) but with the 3rd/1st person view where you can play as ANY race and occassionally have to purchase expansions like Dawn of War or Space Marines expansions for Exterminatus, I am in. Still going to follow Eternal Crusade until launch.
So in short......IMHO myself and many others ARE PAYING enough for everything else 40K and GW/BL & FW. If you like to play MMO's awesome! I hope you enjoy it.
The Emperor Protects & Death to Heretics