I don't see the actual plan. Governments are trying to slow-down the spreading to ensure the medical system will not become overwhelmed. But my guestimation numbers say it can cannot be the way.... take for example Italy.
It seems that Italy cannot handle more than 5000 new cases per day. More than this overwhelms hospitals. There are 60 million people in Italy.... If government enforces severe restrictions to keep new cases under 5000, it will take 4000 days (11 years) until 1/3 of population obtains the immunity. But Italy cannot stand 11 years of quarantine.
So what is the actual plan?
a) To increase the capacity of hospitals so that the daily limit of new cases can be increased to 50000? Yes, it can be done in less than 11 years, but quite difficult now, under 'fire'.
b) To wait and hope for a vaccine or a cure? Can this be called a plan at all?