Well that's actually the point of my final sentence, this isn't possible. The blowout in applications vs spots over the past 5 years effectively means that no new applicants now will ever be granted the visa. Even if a child is willing to accept full financial responsibility for their parent(s) there's no way this visa can actually (effectively) be granted.
They need to either:
A) Pull this visa from list of visas or at the absolute minimum provide a realistic timeline - it's misleading and dishonest to suggest this is a realistic option for most people anymore. The website quotes 5 years when it's actually >20 years now. Immi is just collecting >$4k from people on the misguided belief this visa can be possibly granted to them based on the info immi is providing, which is no longer true.
B) Amend the visa to make it far more 'contributory' in nature. i.e. either massively increase the fee, increase the AoS period, or add some additional conditions that shift the financial cost more onto the sponsors. If costs can be more adequately recovered then I believe family's ought to be permitted a realist opportunity to reunite. Not every argument needs to be a strictly economic one 'how much can this person add to Aus GDP over their lifetime' - there is a human element to humans and in many cultures looking after one's parents in old age is really important. Our country is one of migrants after all.