If a sunset scene has a total of 17-stops between the sky and the foreground and the camera has 13-stops of in-camera dynamic range, a 2-stop soft GND and 3-stop hard reverse GND would cover that exposure gap (12 + 2 + 3 = 17) range is usually 15+ stops, which is currently too far beyond the capability of modern sensors.
Another way to think about it is that a GND filter expands in-camera dynamic range by decreasing highlight zones, similar to how the Zone System by Ansel Adams works in the darkroom.
A post-processing technique such as HDR could be used to give the impression of expanded dynamic range, but you can lose the long exposure component that is often times so central in the best sunset scenes.