In theory, if Garuda actually go through with this, they could replace their entire fleet with A330neos and do reasonably well.
They could even serve the USA (although would probably be limited to Seattle) with A330-800s.
They could also actually have a viable First Class product if they go for Thompson Vantage First suites, with Vantage XL positioned behind.
8 abreast economy, 7 abreast premium (if they decide to introduce it), 1-2-1 Business and First... it could work. Only issue is how inefficient the A330-800s would be.
But smaller jets, more direct flights, skimming off the highest yields... in theory that will work well. In theory.
Agreed for the most part, for GA the A338 could make sense, for (developing) long thin routes. As for your claim regarding the inefficiency of the A338, remember it is still a huge improvement over the A332 and 77W GA uses now. But, the 787-9 would be even more efficient. So I wonder why GA would want these A338 when they are already have a Loi with Boeing for 787-9s! The only reason I can think of is if GA wants to profile itself as a more premium airline, offering more comfortable 2-4-2 seating over the 3-3-3 Y experience of the 787. But a lot more is required than just adding a new aircraft of course...
146,318/19/20/21, AB6,332,333,343,345,346,359,388, 722,732/3/4/5/G/8,9, 742,74E,744,752,762,763, 772,77E,773,77W,788 AT4/7,ATP,CRK,E75/90,F50/70