A slot is a slot......
Except when it is quarantined for "intra-state" services as per the ACT which nearly all REX slots are.
Just because they have a 730am slot does not mean big brother can chuck an A330 into it.
Qantas have the luxury of having so many Sydney slots that they can swap and change by minutes here and there, just watch metron some days....
Buying Rex does not solve anyone's slot problems.