I'm not sure when it happened, I know DL was after CO though. DL also only has 2-cabin service, they merged First with Business to create Business Elite.

Also not sure it NW was before or after CO in doing this? NW and KL both dropped first class and adopted the product called World Business Class. When AF aquired KL, I wondered if this would change, but so far it hasn't. AF now has 4 cabins of service on international routes.

Personally, think international First is going to be a thing of the past, the trend now seems to be, a good business product, a "premium" coach product, and basic coach. TG offers this type of cabin on it's LAX-BKK route. I think NZ goes this way as well. Will be interesting to see.