“No, James wrote his letter to the 12 tribes scattered abroad.”
Yes, some were scattered abroad, but many returned with Judah from the captivity, the Bible tells us that (1 Chr. 9:1-3). Actually, many left the Northern Kingdom and mixed with Judah even before the Assyrian captivity (2 Chr. 11:13-14), (2 Chr. 15:8-9).
In Genesis, when Jacob Israel was nearing his death, he prophesied to all his sons concerning the last days. Tell me where, inside the country commonly called Israel today, is Manasseh being a "great nation", Ephraim being a "company of nations" and Zebulon being a "haven for ships", not to mention the other eight besides Judah being the scepter good fig in the current nation of Israel. Amazing if you can fit them all in that tiny country.
Also in Revelation, there would be 200,000,000 of Gog and Magog invading "Israel" for their cattle and booty. Why would 200,000,000 troops try to take booty from a nation of 4 million?