The new small SUV's have their place but their fuel economy still isn't fantastic.
In terms of putting the full size SUV's out of business, not going to happen. The GLK, Tiguan, etc are too small for some buyers and they can get a bigger model for not much more with only slightly worse fuel economy.
In terms of putting the Cayenne Turbo and Range Rover out of business, that won't happen either. the GLK starts at $34,000. The Range Rover and Cayenne Turbo cost more than twice that. They're in completely different leagues. There have always been small cheap SUVs and larger, more expensive ones, and there always will be.
The Range Rover is also a niche car that not a lot of people are going to buy anyways unless they really want one. They're extremely expensive, extremely unreliable, extremely expensive to fix, and depreciate extremely quickly (say 50% in 2 years, thats about $40,000 lost in thin air). Range Rovers have never really been known for sportiness or fuel economy either. The Range Rover sport handles pretty well but its still a 6000lb SUV. Anyone in the right mind would buy a Lexus LX570, Land Cruiser, or something that is actually reliable and holds its value well.