Are the coronavirus sacrifices being made purely for Granny’s benefit?

On the evening of 16 April, the ABC journalist Leigh Sales interviewed Australia’s Prime Minister regarding the Government’s COVID-19 response.
One Ms Sales’ questions concerned the fairness of asking younger, employed people to take a financial hit on behalf of society’s elders.
After all, Ms Sales argued, the virus has so far killed only older people in this country (in the age range 55-94, at this writing).
The Prime Minister provided a non-technical answer emphasising mutual responsibility, which was reasonable enough under the circumstances.