The main reason if you read the article is the expectation of the Enhanced 340-600, which will make the residual values of the ordered 346 HGW's much less in the 2nd hand market in the future.
The 345's with the exception of the Ozzie routes maybe, are not being used for what they were intended for, ie +15 hour flights. The high fuel price hasn't helped. Great ship mind, all the same!
EGGW