There was a time when it wasn't smoking and obesity that killed people, but smallpox, plague, tuberculosis, and other infectious diseases. When a single epidemic could kill a double-digit percentage of the entire population of whatever unlucky region got it. For reference, COVID killed maybe 0.2% and HIV killed 0.4% over forty years.
To quote Munroe, our heroes have slain one of the four horsemen of the apocalypse, and here you are complaining about sitting in a cubicle.
Forty percent of the people in your office would have died before the age of five. Many of the rest would have died young of now completely avertable causes. Perhaps something as small as a cut that got infected, or fucking diarrhoea.
The natural maternal mortality rate is something like 1.5%. That's per birth. Because half your children will die, most women will have half a dozen children (modern estimates for hunter gatherer fertility rates). Do you feel lucky? Another reason women had half a dozen children because reliable birth control wasn't a thing.
You know what else wasn't a thing? A working justice system. You may fantasize about a just and noble justice system that runs on tight-knit personal connections in a small village where everyone knows each other, but everything we know about criminal justice tells us that small insular groups of people are actually terrible at justice. My people mete out justice, your people punish on whims and gut feelings, they are extrajudicial lynchers. Actually we're all extrajudicial lynchers, because no judicial system, remember?
I could go on, but I have to finish reading my printed book teaching me the fruit of thousands of years of accumulated wisdom. (I'm a grad student and I'm trying to learn quantum field theory). It took me two hours of my underpaid grad student labour to make enough money to buy the book. I bought it because I like reading paper books. I could actually just download it and read it on my LCD display connected to the entire world's knowledge. That laptop was a bit more expensive. Maybe two weeks wages. For reference, it took maybe ~500 hours labour to make a shirt in medieval times. When they had division of labour and looms. Hope you don't mind wearing the same animal hide for years on end.
But you're certainly right about the problems with child mortality, maternal mortality, birth control, and infected cuts. I think it's not a given whether or not these are necessarily deal-breakers (personally I think the maternal-mortality-plus-birth-control combo is the most horrifying, but YMMV), but they're certainly very huge problems. Very huge problems.
But I am not so sure you're right about problems with the justice. Again, GP didn't talk about the wonders of 15th-C England or 3rd-C Rome (never mind the really bad eras), they talked about pre-technological hunter-gatherer societies. Since "justice" is just a fiction we've come up with to try to match our evolved intuitions, my guess is that we'd be happier with the justice of that era than we are with the justice of the present era (and I agree that the present-day first-world situation is much better than pretty much all of the alternatives in the last 10,000 years). But you made a particular claim here, that "everything we know about criminal justice tells us that small insular groups of people are actually terrible at justice", and so maybe you have some references you'd care to share that could help me understand how right you are. I'd appreciate that.
Personally, I, too, am a pretty big fan of printed books and (the output of) looms. (I mean, I'm actually a big fan of LCDs, too, but I think that's a less obvious win.) But I think that your final paragraph is basically begging the question. My understanding is that existing hunter-gatherers (the very very few of them that there are) are actually happier.
The real problem with wanting that lifestyle is that it has a huge footprint in terms of relatively-good land required to support a small group. That's even true for the best land (places where fish just come to you, like parts of California or British Columbia), and it's even more true other places. So agriculturists can raise 100x the population, and thus 100x the army, on the same land. And they do so, and then they take your land.
So to me, the answer to 0xbadcafebee is:
nope, not unless you have a way to buy a lot of land and keep the surrounding culture at bay
This is of course because they were pretty long-lived, but had a high infant/childhood mortality rate. It's certainly a way to look at it, but if you counted every miscarriage as a negative lifespan, you could make the average lifespan even shorter.
When hunter-gatherers lived past childhood, they lived almost as long as we live.
It's all fun and games until you stub your toe and get an infection that could be treated with antibiotics, well except by choice you don't have any and you get to watch your body rot until you die.
A species that spends more time living in a techno/economic LARP fantasy world than dealing with very obvious and real problems has extremely limited survival prospects.
From that POV the transhumanists already won.
Practically - here we are, self-defined as a huge success while our cities flood and/or burn.