That'll happen when there's more people infected than medical resources to deal with them, and world-wide, you won't be able to buy in more resources. Wuhan has far more capacity to care for people because of previous investment thanks to SARS.The potential economic collapse is also a potential health disaster. You create a situation where medical supplies and pharmaceuticals become rationed and otherwise mild medical conditions become life threatening and further drain on health care.
The stupid thing with the economic damage is it's man-made and completely artificial. Everyone stops working because no-one is working; the actual human capacity to remain productive isn't hindered by anything except the social rules as to when people will and won't work.
That's the plan, but at the moment no-one knows how much action is needed to slow by how much time to reach an unknown deadline when some sort of vaccine or cure becomes available, which may be a year or more away. The public taking it seriously enough to actually apply proper hygiene and make sensible choices is going to be essential to slowing it enough to have at least a shot at a medical breakthrough before human cost is too great.The response needs to be measured to prevent a different crisis and hope to slow or contain covid-19 enough that an immunization becomes available.