The shabbats (sabbaths) of the land and the Yobel (Jubilee) are not about the U.S. or other countries, but about the land of Israel. Yet even in the diaspora (outside the land), there are lessons we can learn about how we should trust in God, how far God can take care of His people and how we are to take care of our families and each other.
Keeping the jubilee year with both crops and servants were an act of faith on the part of the people of Israel. It is difficult to live in freedom of liberty and it is so easy to fall into bondage and slavery. God set up a safety net to protect the people from permanent bondage and slavery and to protect the land from being over consumed and dried up.