Short answer: Most national governments think in the short term and only of themselves.
Long answer: National governments (and national policies) tend to be short-term, results-based strategies that (a) either help the government stay in power, or (b) pursue “my country first” strategies.
The problem with that is that bringing serious change to another country, with food, economic aid, or other social changes – is a generational, long term, slow results investment. Not something where you see immediate results. TO make a difference in a country like Ethiopia takes decades.
Most politicians (including contemporary ones) are after a quick fix, feel good type of return.
And when changes, in the poorer countries, it often benefits the donor, helper countries – if they had the patience to stick with it.
Take China – honestly, they are doing it right these days. They are making long term investments and commitments that may pay off in 20 years.
The US is doing it wrong. We’re letting China eat our lunch all over the world, because of our stupid-ass America First policies.