from the perspective of 100,000,000 years later it is unlikely that the most critical point in this part of history will have been the distribution of enough malaria nets

I read this as presuming that generating/saving more humans is a worse use of smart/rich people's attention and resources than developing future-good theory+technology (or maybe it's only making more malaria-net-charity-recipients and their descendants that isn't a good investment toward those future-good things, but that's not likely to figure, since we can save quite a few lives at a very favorable ratio).

I wonder if you meant that it's a worse use because we have more people alive now than is optimal for future good, or because we only want more smart people, or something else.