Are God's offers to Israel still valid even though He knew they would fail?
Yes. The context states these things are all valid offers even though God knows the nation will fall far short of all this. God's intention was for Israel to be a nation of go-betweens, or priests, and a light to the Gentiles, as Isaiah 49:6 declares.
Les explains that Isaiah 49 presents God's concept of Israel becoming a nation of go-betweens, or priests. He emphasizes that these are all valid offers, even though God knows the nation is going to fall far short of all this. This connects back to Exodus and Mount Sinai: if Israel was obedient to the Law, the covenant God was giving them, they would be a channel sometime down the road to funnel salvation into the Gentile world. In Isaiah 49:6, God says it is a light thing that the servant should raise up the tribes of Jacob and restore the preserved of Israel; He will also give the nation Israel for a light to the Gentiles.
More Questions
If God knew Israel would fail, were His offers to them still genuine?
God's offers to Israel of being a kingdom of priests were valid, real offers even though God knew the nation was going to fall far short of all of it.