Why hasn’t a more serious attempt been made at identifying and bringing descendants of the other tribes to Israel?

Israel is named Israel, not Judah, and yet we hear so much about it being a Jewish state and all this, but why then aren’t they trying to find more descendants of other tribes to bring in? I know Samaritans are there but if the point is to be Israel, not Judah, then don’t they need the descendanta of other tribes?