The post office workers in the UK who where f-ed over by the government because the software was reporting things incorrectly could really have used this as well. Should all our financial systems be open source too?

Maybe it should be like Copyright or patents, you can keep things private for a while for an advantage, but then you would need to release all code as open source / public domain or similar? It should also be available before that to be reviewed by professionals following a formal process of some sort.