Pretty bloody much. They were literally raiding old RS-25s and unlocking the secrets of the STC for the F-1.
With that said, what is left of this debate?
We've discussed how far back we'll revert to realistically in the event of an apocalyptic scenario.
We've discussed how sloth is irrelevant as a tech killer.
We've discussed the unlikeliness of the death of knowledge with current factors.
We've yet to discuss the death of skill.
Before I begin, I would like to sub-quote Horus; automation is like war, rarely personal, mostly business. Companies adopted them not because they're personally lazy to mill things themselves, but because its fast, its cost effective in the long run and its safer.
Sure you can remove all the automation and fully depend on experienced skilled labor, but they're expensive and rare even in the past, you'll end up sitting around waiting for new employees to man the machines, especially with today's massive production demands, it would do far more harm than good.
Even if we're to cut our world population from 8 billion to 2 billion. We'll still struggle without automation.
About the Death of Skill? Recoverable.
Machinists work most of the time with manual machines especially in the beginning, if they're lucky, the company they're working for might have a CNC machine for them to work with. However, even if you take away the CNC from a CNC lathe, you'll get a lathe, and the machinist will still know how to use it because that's what he was taught with. Within a decade or less, he'll be able to redevelop his own unique set of skills for precise turning.
Take America during the cold war for example. The people working for the space program took their sweet time developing their rockets until the Soviets sent up Sputnik-1, at that time no one had any real experience nor the skill to outplay the Soviets. As the old saying goes, everybody gangsta till the sky starts beeping. Long story short, even with America far behind in rocket technology, they still managed to reach the moon first.
With that, I'm not worried about the loss of skill, because their practice is still very widespread amongst smaller factories and hobbyists who have no funds or no need for CNC. Plus it is recoverable, if we start with nothing, we can always develop it our own eventually. If we lose it, we can always rediscover it, albeit painstakingly.
This is nothing to lose hope over. Unless we start over-relying on AI, I don't want to write my view points on this topic, because Warhammer's Dark Age of Technology lore already covered many of my points well, plus its far more exciting.