And, more recently, the bursting of the bubble economy in the early 1990s led to debt overhang and excess labor, which further increased the burden of such adjustment. We hear anecdotes that the delay in corporate restructuring has kept competent human resources in existing firms, and this is one of the main reasons for the low rate of new business openings in Japan.
We might be comfortable in having an overall framework that is robust to these changes in circumstance, but it may well not be possible to distil that framework down to a set of quantifiable models that can be useful in practice. Hence the aim is to make the system robust, whatever the right model.