So to paraphrase: doesn’t matter for developed nations, we don’t have an answer for undeveloped ones.
…doesn’t that suggest it would be worth a billionaire trying to find an answer for the latter? A way to help local farmers feed their population? It seems like an interesting problem space to me. Certainly more interesting than replicating space flights NASA already did decades ago.
Hunger is basically a non-issue in all developed nations. See all the gray and purple nations on this map. In the US, for example, deaths from malnutrition are ~,1% of all deaths annually. Any money the billionaires might put into it would be better spent on traffic safety, reducing cardiovascular diseases, or researching cancer, and those are all by several orders of magnitude. https://www.worldlifeexpectancy.com/cause-of-death/malnutrit...
Also, aid sent to the countries that do have hunger problems (like much of sub-Saharan Africa) has simply crashed their agricultural economy, making the issue even worse. Local farmers can't really compete with free, after all.