The only workable answer is for lots of distributed planners to make lots of real-time decisions based on pertinent information. Most of them will make bad decisions, but a few will make correct ones, and hence win.
Centralization and a bureaucracy applying a decision upon a large territory is a good recipe for disaster if the decision is a bad one.
Any "overnight flip to" anything is often a bad decision.
Moreover the real cause is an economic crisis centered on a foreign exchange deficit: http://www.srilankaguardian.org/2021/07/sri-lanka-manufactur...
They "predict" that they will lose 50% of the harvest. Let's not call it a failure just yet and see how this turns out after a few years.
Sure, sudden change is disruptive, but humans are adaptable and can accomplish amazing things in a crisis. If they don't revert it and stay organic only, maybe they'll have an amazing reputation and a huge competitive edge in a decade.
Yes, the population can adapt downwards as people starve or migrate somewhere else. After a decade or so, the people who are left will be in an excellent position to sell organic tea to middle-class Americans.
Similar arguments were made in defence of collectivization in the 1920s. The complacency is astounding.
They won't have an edge. The green revolution is what allowed population to boom.
Now some people are like "yeah, let's go back to before"?
Sounds a lot like the people who shun vaccines and medication.
Time and again we see this top-down police push that don't consult key stake holders (farmers, merchants, consumers etc.,) or fail to consider their feedback ending in a disaster.
To top it off they rolled it out 100% (No A/B experiment, so to speak). These big changes have higher order effects that manifest post launch and can't easily be predicted. They denied themselves a chance to adopt to those higher order effects by launching it overnight. The result is not too surprising.