Sure, an economy can survive without capitalism but it's a pretty meagre existence. Just look at North Korea - it resorts to criminal online attacks and the majority of its people live a subsistence lifestyle where one major problem like a year of drought would have dire effects. Even China was a shell of its current self before it started to embrace capitalism, before that Mao drove millions to their death through stupid policies that caused mass starvation. The Soviet Union is another example of failed central government - which can prop itself up for a very long time, but also collapse rapidly with just a few of the right catalysts coming together at one time. However raw capitalism can be very dangerous too, as corporations don't necessarily have the best interests of the wider population in mind and need to be effectively regulated.