Not Dismissed.
Cathay have not dismissed the idea entirely. Talking to a now ex GM (who has recently moved to an Oz basing) he stated that Cathay bought the last 2 A330's for the sole purpose of locking in the launch customer price of the A380 in case they decide to go down that path.
CX did not need another two A330's but did a deal with Airbus to keep the A380 price down and options open.
One wonders that if Boeing had the -800 pax version ready to go right now, how many airlines would have ditched thier 380 orders and just taken that well proven path instead.