The reason why there will an economic depression and massive unemployment after this short interruption to the business of making money is that most of the world’s wealth is in the pockets of just a few people and they have no intention of giving it up to help other human beings. If the money that sits in the bank accounts of the rich sat, instead, in the bank accounts of our nations, then we could have used it to deal with the pandemic without there being any disastrous long-term effect. It would have been like a person with money put aside for a rainy day who is unemployed for a short while. On her return to work, that person is poorer but not destitute and not in debt.
After the pandemic is over, nations and individuals will be greatly in debt, even destitute, whilst the wealth of the world remains, mostly untouched, in the bank accounts of the obscenely, wealthy few doing fuck all to help anyone.