What happens if we stop monthly demand forecasting?

You may like to take it as a thought experiment. It forces you to think how the entire supply chain will be managed without the monthly forecast.

Can it be done at all?

All of us have experienced it. Yes, monthly forecasts were rendered practically useless when Covid hit us. The following few months were also run by most companies without a monthly forecast.

If you can run your supply chain in such a scenario, you already have several useful agile capabilities embedded in your supply chain. These are just lying dormant. Why not revive them?

Any company can make its supply chain more agile by starting with this thought experiment, identifying what works, and developing capabilities for other processes which would break down.