I still don't think its accurate to say planes with age greater than 10 years undergo "many many many major overhauls, to include electronics"
United's 777's were mostly delivered between 1995-2000 and I bet the only major electronics upgrades were to the passenger entertainment systems.
That's the point, isn't it? Hopefully citizens in those countries will wish that they weren't embargoed and put pressure on their government to change.
I understand that not everyplace has a representative democracy with regular, free elections like the US, but except for the worst dictatorships that rule by force, the government must remain popular with the people!
The trouble with being poor is that it takes up all your time.