Doug,
the covenant of grace was first offerred to the Jewish nation. Remember that Jesus did not go to the gentile people at all. (people of the nations). He went to the lost sheep of Israel first to tell them to repent and turn back to God, Only after christ's resurrection was the invitation to enter the covenant of grace offered to non Jews. See Matthew 28:19,20 and Acts Chapter 10.
Please do not think I personally am saying that the covenant of Grace is better than the Mosaic Law covenant, I was repeating what the Apostle Paul was saying "God saw something better for us", meaning a new covenant based on faith in Christ by Grace and not by observance to laws or works. Again, I am only bringing out what the Christian scriptures teach. For the natural Jews at that time who did accept Christ and enter this covenant, the Mosaic law decreased and eventually became absolete because "for them", Christ fulfilled the law.
I disagree on the interpretation of Jeremiah 11. I firmly believe that jeremiah was fortelling the New convenant arrangement made through faith in Christ. We believers in this covenant have had God's laws written upon our hearts by the power of the Holy Spirit. I think where you are in error is believeing that since Jeremiah was addressing the Jews that Gentiles would not be included in this "new covenant" that Jeremiah spoke about. But as already brought out, few Jews entered into it. And at the time of Jeremiah's writing he did not know yet that God would offer any invitation to people of the nations.
The scriptures I already cited show that Paul said the Jewish nation was first invited to a new covenant with God, one that was better than the Mosaic covenant because it was not contingent on following every letter of law and that most declined this offer because of lack of faith and rejecting Jesus as the Messiah. Then non Jews were given the same invitation to come into a convenant with God thru Jesus and they responded abundantly. Thus Jeremiah was fulfilled and continues to be fulfilled today.
As for most of the Natural Jews today, they continue to live under law. Peace, Lilly