When there were still stats being published for WD, they were always significantly worse than HGST, even long after WD bought HGST. I'm wondering why they keep

When there were still stats being published for WD, they were always significantly worse than HGST, even long after WD bought HGST. I'm wondering why they keep maintaining two product lines that are sufficiently different to result in one basically being consistently the best, the other being consistently the worst, in terms of reliability.