As noted in another comment, I wouldn't consider Polonium to be "harmless."
But I grew up in an environment that would cause most parents, today, to defecate masonry. I grew up in Africa, and we had some really fun critters going through our backyard, like Black Mambas, Gaboon Vipers, and even the damn bugs were nasty. Bug bites could hurt for a month.
I somehow survived.
Citation needed. Radium paint was hazardous to workers making the watches, but alpha particles aren't getting through the crystal or movement and there's not a huge risk to wearing them.
Also, back then, they had radium philters (tonics).
https://en.wikipedia.org/wiki/Tritium_radioluminescence#Smal...
But it was just "minute traces."
It was also commonly in record and camera cleaning brushes, as it could be used to induce a static charge, which would attract dust. Likewise, encapsulated, so the risk with normal use was minimal, but again, if you ground the brush to dust and ate it, all bets are off.
Never had kids, huh?
What changed was that the wall of secrecy broke down and stories of pollution, corruption, and all around bad behavior hit the public like a tsunami. Then we learned that governments had been lying to us over things like Vietnam, with the Pentagon Papers, Watergate etc. Pretty hard to be positive after that. The computerization of the 1970s through 1990s was broadly positively perceived until the 2000s when it became undeniable that Big Tech would do anything to harvest users. Cambridge Analytica. Cutting off Netscape's air supply. Embrace, extend, and extinguish. There are not many reasons to be optimistic.
Nothing you listed actually helps most people.
AI? Another way for untalented people to fake it and profit.
Self Driving Car*. Waymo, everything else is trash. Mostly putting a human out of a job.
Access to space? Great for academics and strategic defense. Maybe the common man will get some transport benefit out of it? Not yet.
Autonomous drones? So we can kill each other better. Oh and the drone shows, definitely worth it.
Flying cars? Ha. Hahaha. Ok. A trained pilot got crashed into while landing at an airport, this year. It’s not going to be a thing without being fully autonomous. But killing people probably makes more money.