Gaming isn't all hours in front of the TV playing games you love. It's big business, and in the case of The Old Republic, it's the biggest single project in terms of R&D expense that EA has ever had. But according to the story on Gamesutra EA thinks it's worth it. While EA CFO Eric Brown didn't put a dollar amount to the likely investment, but says swords and knights (in the form of lightsabers and Jedi) are the most popular (aka sells well) form of fiction in gaming form.
He says EA is being intentionally vague about release, which I think comes in part from not wanting to trample the existing Star Wars MMO Star Wars Galaxies. The rest of it comes from the fact that MMO development takes a lot of work, especially for one this ambitious with different worlds representing each class. I can only imagine what the long term profitability of The Old Republic will be, but I'm sure there's a good chance it'll be profitable before even EA is prepared for.