I don’t buy it. Some pretty flea bitten African countries have been able to operate SU-27 and derivatives. There would be a pretty slim chance those countries could keep an F-16 in the air let alone an F-15. Even the Luftwaffe was able to operate Mig-29 for quiet a while and Poland is keeping its 29’s. Vietnam is having great success operating the SU-27. I cannot think of any countries at that level of development that can sustain frontline US fighters without a huge number of US contractors.