Game companies won't pay for "concepts", there's a million and one already thought up. And the producer/investment group of the title is who gets to make the final decision on what the game includes or doesn't include. And E.A. owns most everything now, and only wants to keep making shitty sequels that sell every year, like (the eagerly-awaited) "NFL 2007", "NBA 2007" and "MLB 2007" (NEW TEAMS!!! DIFFERENT JERSIES!!!! A FEW MORE DIFFERENT PLAYS!!!!! :O ).
Over the last few years a lot of the US game industry principal personalities got hired after producing very popular mods of existing games. If you want to get hired, basically you make cool stuff and let everybody play it. You do not need a "portfolio" in the traditional sense anymore.
Also--most of the people who work at game companies don't get paid very much; it's college kids who do it for a few months because they think it'll be cool. There tends to be a LOT of turnover from when a game is started until 1-2 years later, when it's finished. A lot of times nobody who began working on it is there when it's finished, and most games that are started get scrapped and aren't ever completed.
~