They have 60+ rack units with little robot grabbers physically controlling the knobs.

Re analogue summing, yeah it does near nothing in reality. What you're missing though is that what people actually want with analogue summing isn't really technically better sound but technically worse sound. Analogue gear might have a little bit of harmonic distortion, a little bit of crosstalk between channels, certain transformer characteristics etc that theoretically make it sound more glued together or warm etc etc. But ultimately summing is summing and those differences vs. digital are very small (and won't always contribute positively either).

I personally think analog summing is a waste of time, because the differences are too subtle to be worth the investment in setting it up. But that's just my opinion. Some people are really into it (Eric Valentine comes to mind).

Just wanted to point out that in the context of audio equipment (both professional and audiophile) "sounds better" often means "sounds worse but more engaging". Just like a polaroid picture often evokes more emotions than a photo taken with a modern digital camera and a great lens.