Ex epidemiologist here, fwiw. With shared ambition to go fully pandemic with actionable stuff, also fwiw.
When numbers are less than expected there's a myriad explanations but I'd look at the denominator: How many have read this and do they have everything already and are we really targeting a different population that have different immunity to offers?
I live in Scotland. Rocket mass heaters yell "regulation, insurance" so I won't look at them much, but would love people capable of installing them to do look at them much, so maybe that's an angle. (Locally there's current David vs Goliath fight re windfalls owned by other countries.)
Yeah, also price and ecosystem and soon to happen migrations. (I'm a catastrophologist with years of flu planning. Only worst cases, thank you.)
So, in practice, to judge impact (and to do better!) I'd say look at the underlying structure of the intended epidemic, as numbers only tell part of the story.
Also, in case it helps, I saw something on twitter a couple of days ago, tagged @paulwheaton, by the guy from @lowtechmagazine. They were talking hot water bottles, which tells me there may be many more people in the lower steps of the ladder. Stoves are hard for most.
