How likely is a total economic collapse due to the potential coronavirus impact?
As a disclaimer, this is not an answer, rather a long-form explanation of the difficulties of answering.

The first leg is uncertainty about the danger of the epidemic. Economists are not medical experts. For example, one could imagine that there is an amazing breakthrough where a common medicine saves patients. The economic effects of that scenario are very different than the scenarios presented by governments. More realistically, we do not know how strong activity restrictions have to be to control the epidemic.

The next leg of uncertainty is the government response. Governments have the capacity to bail out entities (firms, households) that get in trouble. We do not know what they will do.

Even if we knew all that, there is uncertainty about the best model that takes all this in. It is very unusual for governments to restrict economic activity in such a broad-based manner, and so there are no standard models. (There is a flood of research.)

Finally, “conventional” economics does not really spend much time looking into societal collapse scenarios. There are areas of academia that do this, and there is presumably studies in economic history. Experts in those subject areas are not normally visiting this website.