"Had a similar experience with a manual earth t-auger. Really quite fast, easy, a pleasure to use, when I wasn't hitting rocks."
Having acquired quite a bit of experience drilling post holes over the last 1/2 year, I respectfully but vehemently disagree. The context: I bought some land last year as an experiment in how much ecosystem services a city dweller can provide himself, for his own family, when having that land next to the primary residence isn't possible. So it's both about being low-tech (for several reasons - price, accessibility, operator skill level required, self-reliance, ...) but also about being efficient enough to let 1 or 2 people work enough land to do something 'useful' on; in my case about 1 ha (2 acres) but I think the same would hold for half as well as 5 times that. I started with a cheap t-auger, which I broke literally on first use (I hadn't even gotten 10cm (~3") into the ground), then a good auger with which I can put up fence poles at a rate of say 15 a day. (it takes between 9 and 25 minutes with a median of 18 minutes to drill a 50 cm (1 1/2') hole, ram the pole down another 20 cm using a ramming block, and side fill the excess space; this is in medium heavy clay soil with quite a lot of stones and subsurface roots, so it is pretty much worst case scenario).
Then I got a gas-powered drill with which I can place posts at a rate > 1/10mins, so almost double the size of doing it with a manual auger; furthermore, it's possible to keep this pace for much longer than with a manual auger because it's much less tiring. So I think you can put in > 40 posts per day with a gas powered machine (but I haven't measured or done this yet).
I've had similar experiences using hand drills, screwdrivers and various kinds of saws, but I haven't measured as much for those.
Anyway my point is - of course you can do everything by hand if you spend enough time. People used to dig canals by hand all the time. But for the modern person aspiring to self-sufficiency and not having access to cheap mass labor that was available in the heyday of manually powered tools, making the best possible use of power tools (given constraints of availability of electricity etc. of course) is very important. In other words, my initial goals of using hand tools didn't quite survive impact with reality, and the first big lesson I've learned from the ordeal is that the romantic notion of using 18th-century-and-earlier technology isn't really feasible for practical purposes unless you go all-out in living like it was back then. (so I mean, people survived back then, so I don't see why it wouldn't be possible to do it again if you go all out; but if want to keep one foot in the modern world and see self-sufficiency as a part-time or fallback thing, like the vast majority of people into this sort of thing do, you have to mix and match to increase your efficiency).