I'd argue that the shrinkage of working age populations is at most an indicator of decline rather than collapse, and given the rise of automation, there really isn't a good historical precedent to predict this from.
The rise of automation, so far, is nothing. The rise of offshoring is. Its not like we automated away the production of consumer goods - we just get China or Taiwan to do it.
True, but the possibility of increasing automation, particularly as a response to a future decline in the size of the working population, is one that hasn't been present in prior historical eras where the working population shrank.