Were Israel's promises earthly even during their physical life?
Yes. Israel's promises remained earthly throughout their physical existence. From Abraham onward, Israel was taught they were a special, called-out, separated covenant people, and all their promises were earthly. They are God's earthly people, and even in the flesh their promises were earthly, including material wealth like Abraham's.
Les teaches that from the very onset of the promise to Abraham until Israel was dispersed after rejecting their king, Israel had it constantly drummed into their mindset that they were a special, called-out, separated, covenant people of God, and all their promises are earthly. He refers to them as God's earthly people. Even in their life in the flesh, all of Israel's promises were earthly, which is why so many had tremendous wealth; Abraham was a wealthy man. Les clarifies that this does not mean an Old Testament saint did not go to paradise after death, but concerns their resurrected state: when Jews experience resurrection as believers, they will not be a heavenly people but an earthly people.