GFE and its replacement "nVidia App" are bloated and large, but the drivers themselves are still 600-900MBs each.
That "optimized for Game X" thing where GFE/nVidia App brags that the driver has all sorts of custom relationships with all the recent exciting games is strangely literal in most cases because the drivers include a frankly wild amount of application/game-specific microcode/optimizations.
My first reaction was "that's an absolutely insane amount of drivers", but then I realised that some GPU and printer drivers are already around 1GB.