The truth is, I don't know a lot of HBD holders who hold their own HBD onchain. Seems like a lot of it is being held on exchanges, where the exchange is collecting the interest.

We'll see if and how that changes after the hardfork, which should stabilize the price of HBD and discourage speculation on it. That, combined with the increased interest rates being voted for by Hive witnesses, should encourage more people to keep their HBD in their local savings balance.