VNA has been in growth mode for a number of years, but they plan on a last minute basis, 2 years ago they were getting rid of expats ( as if unaware of 787/350 coming), now that the new planes are coming it is panic stations, as both local and expats bail for better conditions.
So if 777 guys/gals haven't been called it's because they are overwhelmed, with pilot attrition, 2 new aircraft models to introduce and heavy competition both on the domestic front, with their JV in Cambodia and from the Gulf Carriers..
At the risk of being controversial, by the time one makes it to 777 Capt, that pilot is a pretty experienced/valuable resource, not like a newbie 500hr Capt on a 320/737, so why would well qualified 777 crew apply for a job that doesn't pay you for the first month, offers reduced salary for the next 3 and then offers a generally uncompetitive salary.. On Pprune there are many discussions/rants about declining Terms and Conditions, but seems to me that pilots play into the hands of industry management, by leaving a job to come for conditions such as is currently on offer..
Airline execs talk and attend aviation shows and conferences, they are not stupid.
Just a thought!