Do you have an actual quote from Joyce or QF where they have said the business case will live or die on the pilot EA? In all of the quotes I've seen, I haven't seen him make that link. And, he's generally also mentioned pricing, performance guarantees and delivery slots from Airbus and Boeing, as a part of most statements in the business case.
The pilot costs/considerations of any fleet decision are literally a side note in their big spread sheet.
Any business case requiring concessions from flight/cabin crew to "stack up" is by definition marginal.