How is our social system so fragile? I mean seriously - thousands of years and wireless comms and rockets to the moon and not only do we forget to prepare for a virus (something that had happened routinely throughout our history) but when it hits and people have to stay at home for a few weeks the economy falls down and leaves millions of people who want to work unable to do so.
It's just the consequence of market economy. Everyone is under pressure to "cut out fat", make themselves "lean". That applies everywhere across the supply chain. First thing that goes is every redundancy, buffer and spare capacity - things that would mitigate a crisis like this. It's because the companies that "cut out fat" can grow faster, sell cheaper and profit more, compared to their competitors that have risk horizons longer than few months.
What needs to be done is legally mandated buffers and redundancies (so that no one can gain a competitive advantage by omitting or removing them). Many countries had that after II World War. Unfortunately, out of the wood works came people screaming "efficiency!" and cut it all out.