Graduated Neutral Density filters ("grads") come in 1,2,3, and 4 and etc stops of difference, not only two stops. In addition, I shoot film; maybe the OP does too.
Even if you're shooting digital, multiple pictures have to be taken and combined and then edited requiring more knowledge of computer programs that many people do not want to bother with. I don't use these methods so I can't speak from first hand experience. However, for most of the photos that I've seen posted that used HDR or tone control methods, so many are poorly executed and the skies appear very unnatural. So there appears to be a large learning curve with software. Or it doesn't work very easily or consistently. So now the OP has two methods of overcoming the wide range of stops you often are faced with in landscape photos.