As you can tell from the history of the model, Keynesian macroeconomics are very much focussed on demand insufficiency, and government intervention. This was a big deal in the Great Depression. However, the model does not look at supply constraints, and inflation, which means it only looks at the demand side of the equation.

In your view, how important - given recent events such as the COVID-19 pandemic - are supply-side issues to macroeconomics?