As to the RRW, Congress won't fund it, so we are spending significant resources to attempt to troubleshoot problems on weapons that were only designed to be deployed for fifteen to twenty years.
Simulation has been great, but it is no substitute for hands on work, whether addressing urgent needs with the W-76 or B-61 weapons or proceeding with the RRW, none of which is possible without additional budgetary resources and scientists who can finally get their hands on these kinds of programs.