The hypothetical perfect >$50k speaker is an interesting topic in itself. Now that you mention it, I'd like to see something similar - an absolute end-game speaker that doesn't require separates.
An 8C or Kii 3 type approach to a nice looking floorstander that is no-fuss enough that you just put it in your living room, set it up and then forget about it.
Built-in subs.
Purifi or Hypex amps.
DSP and included mic for tuneable EQ and room correction.
Roon, Spotify, etc. support built in.
Even include HDMI eARC/CEC so you can just plug your TV into it and not mess around with another remote when you just want to watch TV.
At $50k I'm sure people might be worried about points of failure or obsolesce, so it should be easily serviceable with modular amp plates, replaceable input boards and upgradable firmware.