The economy rises and falls due to various factors.
A more recent example is the one we live when it was declared that the world was suffering from a pandemic. The prices of oil, the stock market, bitcoin and cryptocurrencies fell, the uncertainty, the blockage of economic activities all together makes the economy move slowly.
In times of a rising economy, it is due to the fact that there are good market policies to satisfy the supply and demand of the goods and services of nations.
But the strong economies like China recovered so well that it makes you wonder if having flexibility among all nations could have reduced the impact of corona virus. Because of the poor planning and terrible structural planning by various countries the corona virus is looking even more dangerous than it should have.
A better approach and the vision to fight the virus rather than hiding might have saved the economy from dropping because locking people in their house was important but not necessary as they could have increased the testing and made managed more patients by allowing more patients and increasing the beds.
Hiding from a problem and locking yourself in will only prevent you but if you fight with it, you either win or loose. Think about it deeply and you will understand my message.
Quarantine is the most effective way of fighting this virus and I don't understand why you have said it's not necessary in fact it really prevent the virus from spreading more because few people are just going out and those people are the ones who work for their family, to provide them the things they need specially they're all in their houses most of the time, quarantine doesn't mean we were hiding from the virus, it is a very effective strategy to fight the virus, do you wonder why it is implemented all around the world, because it is the right move for us now, "Hiding/quarantine is also a way of fighting the virus", making all people tested for the virus is not a good thing at all, people who have symptoms are only the ones being tested or the people ho have interaction with a person who has symptoms of the virus, imagine having majority of people in your country tested, that will need a lot of funds for the things needed for the testing itself and most likely your government will take loans and that will make the road ahead of you very rough for the government will find ways to get more funds, increasing tax, adding tax to things that don't have tax and it will be bad for economy in the long run.