I disagree. I think it's about pivot time, not having a warmed up stable of skilled workers just in case. Nature never optimizes for that and it shouldn't. We should lazy-load that skillset if and when it's necessary. We have writing to carry knowledge forward. Also, video and other media. People are smart and I'm sure a large cohort could be assembled with the right amount of money in fairly short order. As long as that's cheaper than keeping a battalion ready just in case, then I'd argue it's the "correct" way to approach it.
"What can one do in the face of a relatively shrinking population?" is the more interesting question to me.
As someone whose managed a team before, there is a minimum population of people practically required to sustain a particular corpus of actionable information without suffering severe degradation in terms of said information's application.
Once one ends up below that point; things tend to go the way "from scratch rediscovery required", until such time as the population of people capable of acting on it is restored.
Whether that actually happens is a prioritization decision balancing against everything else that still has to be done.
Innovation stalls, improvements take longer to materialize. Machines become obsolete but there's nothing to replace it yet.
Fewer people in fundamental roles is a risk, a danger to our economic chain. We could become quite vulnerable, even crash.