Thanks! I think your view of small prehistoric groups is correct, although I learned while researching this post that the loss of fire in Tasmania is probably false (or at least controversial). However, the aboriginal Tasmanians do seem to have lost various other hunting and fishing technologies. 

What concrete steps would you recommend someone do, if they're interested in Progress Studies in general terms, and would like to contribute in some way, but don't necessarily know how or have a directly relevant background? Other than the obvious steps of writing blog posts and posting here :)

This is good. I would like (and was expecting to read) some more explicit discussion of exaggerated safety demands, which is sometimes called "safetyism." Clearly the idea that demands for safety shouldn't hamper progress and quality of life too much is present in this essay (and in much of progress studies in general), but it feels weirdly unacknowledged right now.

Indeed, the internet is great at many things but doesn't really replace events and salons and conferences and so on.

The classic old guard problem is compelling, but seems rather hypothetical. I wonder if there have been case studies of fields that have moved fast/slow due to the longevity (or lack thereof) of their practitioners? For example, if a scientific field has been led by someone who lived into their 90s or 100s, did that field move more slowly? Can we analyze that?

Sure, I didn't mean to provide a full treatment of the "should it have been invented?" question. I just wanted to point out that there are many possible lines of reasoning:

1. It was impossible to suppress research on the bomb at all, e.g. someone in some private lab would eventually have invented it
2. It was possible to suppress research in one country, but impossible to coordinate all countries (especially in wartime); eventually some country would invent the bomb and gain a massive military and economic advantage over the others
3. It was possible to suppress research globally, but doing so would have dire moral consequences (e.g. require an authoritarian world government)
4. It was possible to suppress research globally in morally acceptable ways, but doing so would have prevented other useful innovations that were worth the risk (e.g. nuclear energy)
5. It was possible to suppress research and the specific outcomes of nuclear research weren't worth it, but it would have created a progress-negative culture that would have destroyed much of humanity's future potential
6. We could have suppressed research without dire consequences and simply failed to do so
7. Inventing the nuclear bomb was Good, Actually

These are not necessarily exhaustive. To me the most compelling is number 2, although nuclear non-proliferation since the cold war has shown that we can coordinate to a large extent, so maybe 6 is true or would have been if there had been no WWII. 

This is essentially the debate on whether a specific technology should have been developed. Many possible answers: it was likely inevitable anyway that at least one country would develop the bomb; suppressing atomic research to avoid it would have led to a poorer world; etc. 

In any case we have somehow managed not to have a nuclear war, so even though there's a potential of tragicness, the bomb's invention itself hasn't been so bad in real terms (except for the people of Hiroshima and Nagasaki, of course). 

Thanks! The nuclear bombings were obviously very tragic, though if we take the view that a progress-positive culture is the main criterion for tragicness, the development of the bomb may have been a pretty good period, since it led to nuclear energy and other innovations. 

Assuming the Great Stagnation hypothesis is true, whatever happened in the 1970s to slow down science could be said to be our 3rd most tragic moment. But it looks like our civilization is self-aware enough to avoid a full return to stasis, so fortunately we're not quite there yet.

Basically the exact same thing I said a few days ago! Possibly the thing to do would have been to convince the Athenians to listen to Alcibiades just before the battle of Aegospotami, when Athens lost most of its fleet.