yes, I definitely think this is a complication here. The toy model in this post assumes the only cause is something like direct cash transfers. I think this makes sense as a baseline (for the same reason GiveWell uses cash transfers as a baseline) but of course we can and do find global health interventions more promising than cash transfers and it is possible the effectiveness of these interventions diminishes over time faster than investment returns. However, I do not think this is what we have seen so for in practice. In 2015, GiveWell had 3 non-cash charities they estimated to be 5-10x more effective than cash transfers, but by 2018 they had 7 which they estimated to be 5-15x more effective than cash[1].
yes, I definitely think this is a complication here. The toy model in this post assumes the only cause is something like direct cash transfers. I think this makes sense as a baseline (for the same reason GiveWell uses cash transfers as a baseline) but of course we can and do find global health interventions more promising than cash transfers and it is possible the effectiveness of these interventions diminishes over time faster than investment returns. However, I do not think this is what we have seen so for in practice. In 2015, GiveWell had 3 non-cash charities they estimated to be 5-10x more effective than cash transfers, but by 2018 they had 7 which they estimated to be 5-15x more effective than cash[1].
https://www.openphilanthropy.org/research/givewells-top-charities-are-increasingly-hard-to-beat/