Capitalism requires the 'voluntary exchange of goods'
If there are no goods, there can simply be no exchange. Even when goods are available, people are too afraid of the coronavirus to spend disposable income on non-essentials.
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Capitalism encourages people to go to work and spend their wages on necessities in addition to non-essentials. Employees spend their free time shopping at malls, going to the movies, eating out, and having fun experiences--most of which are made possible by disposable income. The coronavirus has now made all of these experiences unattainable. Even if people want to spend their disposable income, they are now very limited in how they can spend it. Movie theaters are closed, gyms are locked, and restaurants are shut down. Further, without a cure, many people are afraid of leaving their house. They only leave when absolutely necessary. This means that the disposable income that would have been spent on a meal, movie night, or a new car is now being saved. This would normally be ok. However, so many people are saving their money that the businesses that thrive off of disposable income are going broke. When these businesses can no longer make money, they go bankrupt and lay off employees. Even with a vaccine, there is no business for these former employees to work for. With the loss of all of these businesses and an immense amount of unemployed people, the government will have no choice but to step in and provide a new type of economic system to support citizens.
While there will be less variety in what consumers can spend their disposable income on, capitalism will not collapse. Businesses will. In the age of technology, capitalism is diverse enough that some businesses will thrive--like those online--while others will not--like shopping centers. The businesses that thrive will need more employees to keep up with the growth. So, while in the short term there may be more unemployment, the free market will allow businesses to hire new employees and diversify. Capitalism will help itself recover from these circumstances, so there will be no need for another type of economic system.