It's often a series of mis-steps that lead to catastrophic failures such as being suffered by Srilanka. Here are a few that come to my mind, in no particular order.
1. Tourism took a big hit due to COVID lockdowns.
2. They took on huge debt from China to fund their massive infrastructure developments with close to zero plan as to how to reap the benefit of that infrastructure. For instance this airport[1]
3. The knee jerk banning of fertiliser.
4. Corrupt and authoritarian (despite being democratically elected) government favouring their cronies.
News articles trying to analyse look for a recent bad policy choice such as fertiliser ban but one could see that even 5 years ago that Srilankan economy was being badly managed. The ingredients of catastrophe were there and COVID acted as the catalyst.[1] https://www.forbes.com/sites/wadeshepard/2016/05/28/the-stor...
[2] https://www.reuters.com/markets/commodities/sri-lanka-rows-b...