This seems very optimistic. I see no reason to believe that EA will not attempt to make money for themselves through in-game advertising, as well as making money for themselves by charging us to play online. After all, they are a company whose business is to make money.
You're right, and I'm surprised nobody else picked up on this.
As was said, EA is a for-profit corporation, and the objective of EA and other for-profit corporations is to make money. Assuming EA will place ads in the game, and this is just an assumption at this point, I think it's very unlikely that any revenue generated will go anywhere but the company's pocket. Advertisements are mostly just an extra profit generator for the company showing the ads, with some extra customers and/or increased awareness of the person/company/organisation that created the ad. If EA wants to charge us for multiplayer, they will charge us for multiplayer. If they want to make multiplayer free, they will make multiplayer free. The infrastructure required to support online multiplayer can be paid for with the sales revenue from the game, as well as other games EA/Maxis produces. When sales slow down they either outsource the servers to another company, or just terminate online multiplayer altogether.
And anyways, since when has aditional revenue going to a major corporation ever provided benfits to the individual consumer?