Is there a term for when a problem has been solved for so long it falls out of living memory creating a natural breeding ground for people to question why the s

Is there a term for when a problem has been solved for so long it falls out of living memory creating a natural breeding ground for people to question why the solution is even necessary, come up with nothing because the problem is so long gone, and invent conspiracy theories to fill the gap? Nobody is scared of getting polio anymore and one person not getting vaccinated doesn't really change anything --> the fact that they're nonetheless making me get vaccinated must be because of government chips, lizardpeople, big pharma profits, etc etc. More specific than Chesterton's fence or just history repeating itself.