> It may have also been the case, that before industrialization, metal smelting, and anything-faster-than-walking the world was inherently safe.
I would disagree: historically, kids had to cope with other threats - illnesses, toxic or otherwise deadly animals, general accidents that are "tiny nothings" today could cripple or even kill you back then because there were no antibiotics...
Back 200 years ago, this only worked because people bred like rabbits. Partially of course because there was no birth control (or its usage, e.g. intestines as condoms, frowned upon by the church) , but also because if you had 10 kids it didn't matter if all survived and losses were expected/built in. Now with people having only one child or two, these must be protected to ensure family survival, and that is where helicoptering comes from.
> When our workplaces have a spot for our cars and not our children, should be surprised that car ownership climbs and fertility falls?
The other idea would be to provide livable wages again. I am 28 now, my father was barely 20 and a fresh police officer when I was born - but he could solely fund me, my sister, my mother and himself, saving enough on the side for a downpayment on a 100+ m2 flat.
Today? Many young policemen have to work side gigs to make rent, and my s/o and I plan for the first kid in 3 years from now because without us both working (she's finishing her MSc) we don't stand a chance to financially survive, and forget about saving anything or buying a place to live if our parents would not support us financially. And that doesn't even include the question "who will stay home for how much time/reduce their hours".
Provide real wages, limit workdays to 4x6 or 5x6 hours a week (and ENFORCE this) and whoops, there are the children that have been missing. If people don't feel safe they don't have kids.