Fleet
I suspect Luke is on the WB fleet, so his info is somewhat different, on the A321 fleet a number of guys this year have gone to the nameless airline and to EK, and more are waiting for a chance.
VN pays nothing more than your salary and good luck trying to get overtime, school fees are on average +$1000 a month raising to almost $1800 per month for a senior in high school (field trip, laptop etc ). Whilst the cost of living is not that of Dubai, it has risen considerably in the last 7 years.. Factor in the official inflation rate over that period +10% annually compounded and a basic salary 10.8K for 6/2 Capt 321, if your a single guy it's ok, but if you have kids and a wife, not so much. Unfortunately guys often overlook the benefit of a provident plan, until it's to late. For FOs this is one of the best paying contracts out there and they offer a path to the left seat, albeit minus the cost of training and a bond and a 10% pay cut for the first year (approx $60K total)...
As with any airline that expands too rapidly, one calamitous incident may cause the CAAV to revisit the rapid upgrades and put the brakes on! As investment advisors often say "past fund performance is no indicator of future fund performance", there is no guarantee that the upgrade path will continue as it has.