It is the root. It's just it's the racism 50+ years ago not the racism today that's the real problem. Until we address the economic advantages white people had back then and have today due to it we wont solve racism. Are we really just supposed to get rid of it today and then say "time to catch up"? I hope not.
Yes I think it the economic issue has eclipsed the race issue due to the strides we've made against racism in modern times (of which there is still much to do).
I find it very hard to talk about this issue concisely but I'll try. Other races were poor 50+ years ago just as they are today and I believe these poor people suffer many of the disadvantages many African Americans suffer because they are indeed the same.
Edit: that wasn't very concise it seems after rereading it. I failed to mention that I don't think any other race (in the US) has been as totally economically disenfranchised as African Americans were and that is why this is predominantly an issue that affects African Americans.