Capitalism is based on maximum exploitation of resources and maximization of profit. To survive this structure requires constant growth in production of material goods. That is no longer viable.
Market economics is the best mechanism to handle distribution and pricing of goods. That is a distinct system from capitalism. The best example of an alternative replacement is the rapid rise of China that carefully uses controlled market economics but in a managed environment. It wasn’t supposed to work but China will shortly surpass the US as the wealthiest nation. The resurgence of authoritarian trends there may well slow this down but the same trends are already destroying the US.
The old systems are dead because the conditions are changing drastically.