[Claritas]

Is it going to change to suit your changing tastes? If it's adaptive, it might be worth something. Otherwise, why pay a lot if you're going to change and it's going to stay the same? So I'll go with a lowball figure of 3k or so. An AI headphone rig would cost millions.

 

[marone]

I think someone is not understanding the theoretical nature of the OP's question. We're talking about a magical non-existent headphone amp system that is guaranteed to play your music better than any other out there. How much would you pay to have it be yours?

Since the current best costs $5k to $8k, then add a few thousand to that. $8k to $10k.

...but 'better' will come along in 5 or 10 years at the same or lower price and your "headphone-setup-that-is-guaranteed-to-be-the-best-out-there-for-all-types-of-music" will no longer be the best.

Look at the HE-90 and the current top of the line phones that, with better performance, are 1/4th the price.

$10k...that is what I would spend today.

If you want 'silly and wasteful' then a pair of Krell Reference Monoblocks driving a $5k pair of headphones...but why? One twitch of the volume knob and you will fuse the drivers.