The subject isn't about salvation, it's about material wealth and power.
Well if you limit this to Material wealth and power, then obviously yes, those two nations were no doubt blessed with that, but if we use that description as a way to find and identify so called, " Lost tribes of Israel", then explain why we cannot then consider the Soviet Union, China, India, Saudi Arabia, and so on as also being blessed by God?
See, people have a tendency to limit God in many ways, as long as the limitation " Includes THEM." Be it material blessings or power, or even salvation; because certain believers seek to limit salvation itself; and because THEY pick and choose, they feel God does it as well. Which is why I agree with the poster who brought up the Gentiles being blessed as well; because some Jews sought to horde the blessings to themselves. And Paul argued against that.
In the long run, all nations will be blessed with the benefits of Heavens ultimate powers and wealth, in the short run, those who receive it now, is basically meaningless, if we consider the whole picture of what God is after.
If we magnify any blessings received in this life, and brag on them or look to glorify ourselves, then there is a danger in that; because this life is not end of story. When any nation looks to pacify themselves for conceived spiritual reasons, pride is waiting at that door.