The costs would be minimal compared to what they are making off the back of Ultimate Team.
For example, in 2012 FIFA were reported to have made $100,000,000 from Ultimate Team in FIFA's 10 + 11 combined, the mode has since been integrated to come with the game from launch and will be now making more money than ever due to the introduction of buying "Fifa Points" rather than the packs themselves. They will be close to the half billion mark if not higher by now I should think.
And that is just FIFA. Factor in NHL and Madden UT as well and you are fast approaching that $billion mark if you aren't there already.
As I said, it will never happen and I am a dreamer but all it would need is slight tweeks in either direction whilst using the same basic engine. But there would need to be a nod in the direction of FIFA and Madden series to make them more sim as well so as not to single out any one particular game.