Also, I do understand why audio and video would be run to different component cables. It's because it's analog signal that has to be split between audio and visual so that there aren't any ghosting or noise crossover.
What YOU don't understand is how HDMI works or, as it seems, the difference between digital and analog.
Tell me, where exactly do you think you'll find a movie or some other media that has both video and audio, that uses high quality uncompressed audio AND video at the same time that HDMI couldn't handle better than a shitty Analog component?
On top of that, the way pretty much every electronic is these days, it all gets converted to digital anyway. So if that's the case, why convert it from digital to analog back to digital? How does that make it "pro" and not "stupid."
Running separate components made sense when everything was analog.