I'm not sure I really follow how much of that relates to the topic of the thread, but wealthy countries don't generally give aid out of pure altruism, there's usually a significant degree of self interest involved.
I'm not sure how things look in the US now, after all the recent cuts, but pre-Trump, about 25% of foreign aid spending was domestic (e.g. subsidizing US business for produce to be shipped overseas). Tbf, that likely does contribute to soil erosion, in the same way that capitalism often comes at a resource cost.
When aide is spent in developing countries themselves, that's usually economically beneficial, too. The US (and the UK) essentially use aide money to invest in a developing country so that, as it becomes more stable and affluent, they have a new market to sell to. About 40% of US/UK export revenue comes from developing countries.
Its hard to put an exact number on it, but even lower estimates tend to say that the US doubles its money on foreign aid spending - its a profitable investment.
Obviously, poorer countries generally dont have the means to make similar investments in richer ones.
I'm not, by any means, suggesting that foreign aide is purely exploitative, but the economics of it largely explain why its a one-way street, and I don't think it should be viewed as an "unreturned favor".
(Obviously, national security interest, disease control, general soft power, etc, are all benefits of foreign aide too, which likely have economic value, albeit harder to calculate).