Ultra,
Airlink is also a wholly owned Qantas subsidiary, they just don't own/lease their own aircraft.
My gut feeling is that Qantas entered into an agreement with Impulse because they saw the Ansett writing on the wall and wanted to position themselves for the future.
Perhaps if Gerry hadn't started Impulse Jets, your scenario of bigger and better for Eastern & Sunnies might have come true. Perhaps it wouldn't.
We all want bigger and better and seem to think that just because we work for company x, we deserve it. The reality is, IMO, that primarily Airlines are there to make money by serving the travelling pubic, not to give us shiny new machines and career opportunities such as big shiny new jets.
I agree that not to give employees some progression is not good for morale, but I've never believed that Sunstate or Eastern would get jets and I've observed both with various levels of interest for over 15 years. Perhaps the expectation of "some sort of improvement in promotional opportunity" was wishful rather than realistic.
Personally I don't think that any one group in the QF family has any more right to 717s than another, nor do they have less right.