1) While flying around burning fuel the flight crew was also in contact with Flight Engineering attempting to see if anything could be done.
2) I don't think the front gear would retract - thus they wouldn't want to fly to N.Y. with gear down.
3) Weather in LA was perfect.
4) Weather in N.Y. - unknown, but probably DARK. If you've got to manage an emergency it's probably better to do it in daylight.
5) LAX had a very long runway available (4 parallel runways) and good emergency equipment available.
6) If you have a known emergency don't make it any worse! What would have happened had they started to N.Y. and then were forced to land somewhere else due to a different emergency? Good chance the other site would not be as well prepared as LAX.
Just my $.02
"...What would have happened had they started to N.Y. and then were forced to land somewhere else due to a different emergency? Good chance the other site would not be as well prepared as LAX...."
Perhaps an emergency landing at Memphis International Airport. It's been used for emergencies and has excellent long and uncluttered approaches. No towers or tall buildings to interupt any approach that might be needed.