Agree with
@MEL_Traveller here - And while the non Platinum Kids may eventually get to see Mickey, it might be in 3 days time, or 8 days - by which time the trip is likely ruined. As P1, I've been incredibly lucky with such things - earlier this year for example, I was on MEL-DFW - it got nuked the day prior (IIRC) due to an engine issue with the aircraft. QF, to their credit, put me on a flight to SYD, and SYD-DFW - in J, and even in a fairly preferred seat(this I did not expect) - on a reward flight no less. I have no doubt there were customers on that MEL-DFW who were only offered the next departure *of that flight* 3 days later. I don't have any anecdotal example of this, but I'd bet it to be so.
See, it all comes down to an interpretation of "next available" - and surprise, surprise - the next available flight for the customer probably doesn't equate to the next available for the carrier (and to a degree, I understand that - I mean in my example above, at short notice, how many of MEL-DFW pax could they shove on to the SYD-DFW? I didn't look at how the loads were looking for that flight til my flight was cancelled, but you can imagine it was already pretty full as is). Plus, they could have thrown some pax on to services to LAX from MEL/SYD/BNE and then onto AA.
And that's the other catch that seems to be a thing in North America, but not here that much but QF naturally would balk at putting their pax on alternate, non partner carriers - eg: maybe they could have put DFW pax on UA or DL ex SYD, or even potentially NZ - but that would cost them bigly, and they'll do anything to avoid that so they might TELL the customer "The next available flight (for you) is in 3 days..." even if there's seats on another carrier. I'm unsure how much one can push on this - probably the more elite one is, the more QF would be willing to do this, but for regular pax would potentially feel quite intimidated to accept whatever QF comes up with as "next available" and they could probably justify it somehow. OTOH, north american carriers seem a little better to - if they an't do anything within reasonable time on their metal, put you on someone else's. Heck, a mate of mine just today told me about an AC *reward* ticket he had booked from YYZ-MCI coming up (in J). AC cancelled the MCI flight. At first they'd put him on a flight to ORD (why? it's miles away.. who knows) but when he contacted them, within a pretty short time that I can tell, they'd rebooked him into DL YYZ-DTW-MCI - in a revenue J fare no less. That's pretty astounding imo (and perhaps kf88 will point to Canadian customer protection law as a reason). I'd expected a reroute on UA - even tacking on a ORD-MCI or something - that would seem the most obvious/easiest for them. Does it happen all the time? nope. It definitely seems to be a thing in North America though way more than here (I do know some QF domestic pax have, in instances, been put on VA, but it seems quite rare imo).
Now, I suppose a pissed off enough person could document that hey trying to get to DFW on so and so date, and QF told me 3 days later, but I could find a seat on United and they wouldn't put me on it - could take QF to a tribunal and argue it out under the notion of "next available flight" but that's probably a messy process most won't attempt (and QF likely would bank on that with some of their decisions).