Yes Focal, I'm well aware of the fact that raked wingtips have been around a long time. Conventional wisdom seems to think they are more efficient than winglets.
<Raked wingtips have been around for about 50 years but it seems modern wing design has only adapted this philosophy in relatively recent years.
The fore runner of modern raked wingtips was called the Hoerner wing tip, in common use on STOL wing designs.
With a conventional rounded or square wingtip, the vortex is centered around the wingtip. If the wingtip is cut at 45 degrees , with a small radius at the bottom and a relatively sharp top corner, the high pressure secondary air flow travels around the rounded bottom but can't go around the sharp corner and is thus pushed outward.
The performance of the wing depends on the distance from the right to left tip vortices (the effective wingspan) and not the actual measured geometric span. Raked wingtips provide the longest effective span for a given geometric span or a given wing weight.
The raked tip is more efficient in reducing tip vortice drag and is lighter than winglets.>