This is absolutely incorrect. Most of the materials machining advancements to make light aircraft parts had to be done specifically for aircraft. Ship building is completely different and largely irrelevant.
> I can't see why I should trust this line of reasoning.
Because this wasn’t some long line of training from centuries of wizardry. Materials science was a joke 100 years ago. We can do what they did then to learn manufacturing but we can do it significantly faster because we have simulations and chemistry knowledge that wasn’t lost.