It seems unlikely that they'll be retired immediately if everything is back to normal on June 1 - when Qantas resumes its international operations. Although this is no guarantee...
Why would anyone (including a journalist) think everything has any chance of 'being back to normal' by '1 June?'
The Prime Minister, and numerous commentators, have indicated that the vast majority of international flights are unlikely to return until 2021.
AFF aviator jb747 (IIRC) suggested 'October 2021', which to me sounds unduly pessimistic, but who's to say he's incorrect? Time may prove he was on the money, much as none of us who love travel hope that.
Granted, coronavirus is fast changing, but neither the Oz or NZ Prime Ministers have specifically named a date (following the expanded to NZ National Cabinet meeting this week) as to when even Trans Tasman 'normal' flights will resume. It's true that some decisions are made quickly and then announced with not much notice, but so far that's not occurred re this.
Even if Oz was OK (and that's far from certain), whether overseas flights recommence depends upon other nations. Singapore, much of Europe, some other nations in Asia and the Americas north and south are among continents/countries that are arguably in a far worse position than Australia in relation to this virus. For instance, even though Canada is less affected than the USA, it still has roughly 40 times Australia's deaths despite only 1.5 times our population. So even it, as a developed nation, may be slow to reopen its borders (and the Australian Government similarly unwilling to let us travel there, and then perhaps be subject to 14 days' quarantine at Federal Govt expense when we return).