Straight Up Terrain Rendering

There are a multitude of methods for real time rendering of expansive outdoor scenes represented as height maps. Most of these methods are mesh complexity reduction algorithms (ROAM, SOAR, etc.) in many variants. What crossed my mind is that no one just gives the hardware a static regular vertex/index buffer and use a texture to manipulate height in the vertex shader (SM3 of course.) Many methods use the vertex texture methods, but the actual vertexes (verteces?) are generated on the CPU. Why not just dump it all on the hardware and let it do its job? 1-2 million vertexes should not pose any problems for current hardware. Of course, there can be a reason why no one does this. Namely that it doesn't work! I should mock something up and test it, if time permits.