There is something to this. Was it Ethiopia that (at some point) instituted a no-NGOs-on-mondays type policy, after realising that all their ministers seemed to

There is something to this. Was it Ethiopia that (at some point) instituted a no-NGOs-on-mondays type policy, after realising that all their ministers seemed to do was have meetings with the many aid organisations? (No link, sorry.) From memory such organisations contributed something like half the government budget, but all with their own concerns & priorities & need for visible success back home. More generally, I think it's a pattern that governments which have to collect taxes from the masses need their consent, and thus tend to behave better, than governments which do not. Whether the non-tax income is from oil money or foreign aid, it probably has some similar effects.