Analog mixing and summing is not dead, it's just not for everybody.
In most cases analog mixing and summing sounds better. The hardware is more expensive than mixing in the box and the results of an analog mix are (generally) not repeatable, it's part of the artistic process.
Tidepool Audio sells everything from $2,000 rack-mount summing mixers to $75k large-format Audient mixing consoles.
Tidepool Audio sells mixing and summing equipment from Audient, Burl, Chandler Ltd, Phoenix Audio, Rupert Neve Designs (RND) and SPL.