Maybe it's not making them enough money by their standards and they'd prefer to reassign the tiny resources they did have designated to PC over to aid their console department. Going off their product these past few years they could use as much help as they can get. Or maybe EA just don't like PC - one of their leading execs said as much (although I'm sure they'll love PC when Spore hits, providing it doesn't require them to actually make any patches anyway). Who knows, all I really know is a platform that has millions of gamers on it deserves to have the US's largest exclusive sporting license covered, or in the least, if EA aren't interested anymore, it deserves to have the NFL license opened for others to take on.
And you know what the really funny thing is? despite EA efforts to do otherwise by just throwing the PS2 version over and calling it a day, 08 PC was the best version last year, and 07 PC the best the year before. I don't think I came across anyone who gave the PC and any other version both a fair go saying otherwise. The PC has so much potential for a football game that even a bastardized version is better than what they've managed to do on the consoles, and yet they seem to think the problem is with the platform, not the fact they don't try to make the PC version special.
Perhaps this will be a blessing in disguise for a truely capable developer to come along. After all, the PC only needs a generic game, the editing communities can do the rest.