The core hard thing may have been the TPU/RTX GPU. Had commercial industry started shipping fissionable material by the gram in some counterfactual world where the possibility of making a nuke with it wasn’t taken seriously, how long do you think it would have taken for someone to do the remaining steps? As you mention it’s an attractor state and assuming enriched uranium is now readily available, people would experiment, building neutron amplifiers at first. Then they would use the information to assemble a self sustaining fission pile—possibly delayed a few years if the economy is took a dive—and more information gain (and the plutonium) makes the nuke inevitable.
The core hard thing may have been the TPU/RTX GPU. Had commercial industry started shipping fissionable material by the gram in some counterfactual world where the possibility of making a nuke with it wasn’t taken seriously, how long do you think it would have taken for someone to do the remaining steps? As you mention it’s an attractor state and assuming enriched uranium is now readily available, people would experiment, building neutron amplifiers at first. Then they would use the information to assemble a self sustaining fission pile—possibly delayed a few years if the economy is took a dive—and more information gain (and the plutonium) makes the nuke inevitable.