Having actually been at the airport that night, I'm pretty confident that Qantas operating a sales/service counter would have at least helped. If nothing else, it would have meant all 3 staff members on duty could have been actually helping customers, rather than 2 of them sitting on hold trying to get through to the call centre for most of the evening.
Anyway, as I said in the original article last July, this fiasco was caused by a combination of the Qantas website/App not working properly, Qantas filing certain ticket types incorrectly, the call centre not answering the phone and no airport staff being able to help. Yes, the announcement of a lockdown at short notice obviously didn't help. I get that. But I really feel like I would not have been stranded in Perth if Virgin or even Jetstar had flights running that evening.
I'm not sure why you're defending Qantas' failure to sell a ticket to a customer who wants to buy one (on a flight with ~100 empty seats, no less). Is it unreasonable for me to expect this of a "premium" airline?