One other factor to consider....
PARTS.
This is Connie's and Southern's angle. And this is why Focus and Ocean Air are struggling. Connie has his own heavy MX and Southern has a huge supply of parts and their own engine shop.
Plus these carriers will fly and aircraft until it is within hours of needing a heavy "D" check, then park them. This gives them a huge tax write-off, plus they can sell or lease parts from these aircraft they have parked and get top dollar for the parts since they come off an acft that is still flyable (Even though it is within a few hours of not being flyable).
This allows Connie and Southern to lease their acft at very attractive rates to a customer. Something Ocean Air and Focus are unable to do.