An interesting piece, and a good conversation to have. My point below is less about the conclusions regarding the effectiveness of economic growth, and more about a particular section that argues against the role of these interventions in progress.
In Section 3, under the sub-heading "Economic growth as a driver of progress and the limitations of RD", the case against the RCT-backed interventions currently recommended by GW is laid out as follows:
"we do not believe that the vast majority of RD interventions are plausibly among the top 100 ways to increase growth... The reason these things are unlikely to be the best way to increase growth is that they play no role in the causal story of the huge differences in GDP per capita across space and time. To illustrate:
It's correct to say that the specific interventions recommended are not necessary conditions of economic growth on a global scale. They did not contribute to Danish economic growth and welfare, but this is because these weren't necessary - either at all (e.g. deworming), or at the time of rapid economic growth (e.g. one could make the case for HIV education). But this a very narrow form of the argument.
The broader question - and the question has to be broader, if considering the "causal story... across space and time" - is whether this type of intervention might be among the top 100 ways to increase growth. Many of the RD interventions are health programmes that work to combat causes of sickness and mortality that are significant in country-specific contexts. Re-writing the second point above, in light of this, I find the statement less convincing:
"It is not the case that Danish people today are better off than Danish people 100 years ago because they implemented [health programmes to deal with significant causes of sickness and mortality in Denmark]".
Obviously such programmes aren't sufficient conditions for economic growth alone, but the argument above seems to suggest they're not necessary either, which I don't see the evidence for. The ultimate argument of the authors may be that both are necessary, but focusing on economic growth is more effective, which is fine, but this section seems misleading to me.