North West,
I think you have to add to your hypothisis "keeping up with the Jones" Emirates expanded at MAN which was followed by Qatar and then Etihad.
Thjy flooded the market expanding at virtually the same time, with way too many seats leading to Qatar having to cut frequencies.
I think especially Etihad as they are blinded by their links to Manchester City and seemingly having a bottomless pit of money. I am quite sure if Emirates added another rotation Etihad would do the same just to keep up !
Nigel