Winglet design is constantly evolving - Airbus apparently thought the wingtip fences were near state of the art when the A380 was designed. Note that the "split" winglet is a fairly recent development, and the split winglet on the 737 Max is not the same as the one available on the 737NG.
That being said, Airbus does appear to be a bit slow on the uptake regarding A380 winglets. I have to assume it'll require some fairly major structural updates to the wing to incorporate...