I think someone should point out to the Fed that the SUPPLY of long-term government bonds is "low", by historical standards.
This limited supply has the effect of keeping bond prices "high", by historical standards. And THIS has the effect of keeping long term interest rates "low", by historical standards.
If the Fed REALLY wanted higher long term rates, it could simply ask the Treasury to issue more long-term bonds. (Why that has NOT happened is a question for another day...)
Now...
Where do I go to pick up my "Nobel"?
Another factor is corporate debt. There isn't as much of that either. Corporations are flush with cash.