IF those services were in the happy position of being able to sell profitably the very substantial increase of long-haul payload capability which AAR might offer to their fleet ..
But the problem is most of the time you'd get
no increase in payload, just range...
As Beags has rightly said the modern big ETOPS twins have so much "grunt" that you rarely need to think about reducing payload or trading fuel for payload just to meet take-off perfomance requirements. Where I work we've got a reasonably modern ETOPS twin in a variety of variants. The only places on our route network (which includes SAN BTW
) where we
routinely have to think about reducing or limiting payload for performance reasons are a handful which are "hot and high"...and even that isn't the case on our newer variants. In fact on many sectors the Zero Fuel Weight limit is going to cap payload before any performance limit - and AAR won't fix that!!.
Now I'd agree that AAR would allow you to increase range and overfly the likes of (lucrative) BKK or SIN on the way between Europe and Oz ..but does that make economic sense?