Warm fuzzies for calling us Videologic instead of Imagination or PowerVR. Your description of the layers between an application and execution on the graphics core on iOS is pretty good. There's nothing between driver and hardware though.
As for why OpenGL ES is different to OpenGL, it's documented in myriad places. The resulting API might be bad in many ways, but it was never designed to allow easy porting of OpenGL (at the same generational level). It was designed to be small, efficient and not bloated, to allow for small, less complicated drivers and execution on resource-constrained platforms. It mostly succeeds.
Long live mgl/sgl! The mention about hardware dedupe/filtering was more a hat tip to culling sub pixel triangles and early culling of obscured primitives that seems to happen on many chips these days :)
We tip our hat right back! It happens to be pixel-perfect for us in this context, and it's a large part of why we draw so efficiently. Oh, and I still have a working m3D-based system that plays SGL games under DOS!
As for why OpenGL ES is different to OpenGL, it's documented in myriad places. The resulting API might be bad in many ways, but it was never designed to allow easy porting of OpenGL (at the same generational level). It was designed to be small, efficient and not bloated, to allow for small, less complicated drivers and execution on resource-constrained platforms. It mostly succeeds.