How can we make sure NDAs stay intact even if the company goes defunct?

Typically you will have a survival clause in a NDA agreement that should provide details of the rights as well as the obligations of the parties after the period of the NDA or if one party goes bankrupt. However, each NDA has to be evaluated on a case-by-case basis to analyze the rights and obligations of the parties to know whether a NDA with a bankrupt company is void.