And what happened after the Assyrian empire fell? That is not included in “to this day”, which was before Judah fell to the Chaldeans.
Many probably continued to be slaves. But instead of serving their Assyrian masters, many probably had to serve Babylonian masters, and then the Media-Persian masters.
For what it’s worth, in the summer of 07, I was hiking in the Rockies, and was passed up by a couple of young Jewish looking fellows. They were wearing the skull cap things. I asked them what tribe they were from. They said, “Ephraim”.