IIRC, some auto EQ systems like ARC can have its upper limit of correction adjusted, but that many users leave that point higher than expected because there often are enough benefits by doing so in their cases, so far that I can remember.
I can think of a number of high end systems that use them. You have some extremely discerning tastes, but I don't think my own systems are all too shabby, and the ones I think of are definitely high end to me. I even think of a B&W D series mch system, front three being 802Ds, IIRC.
However, don't get me wrong, I respect your opinion and thoughts on the matter. No one would disagree with you that the physics of placements within any specific room itself should be addressed first, or even that passive treatments should be addressed first.
My positive experience with Audyssey MultEQ XT was after enjoying extensive acoustic treatments for a number of months. The improvement with the EQ was almost as good as the passive treatments themselves, in my extremely subjective opinion. Please know that my home has really horrible acoustics, slap echo, etc. It definitely took effort to tame, and it's still not totally tamed by any means. Oh well.
Bear in mind I have had only one opportunity to evaluate that system.
I guess I'm a minimalist at heart. That probably sounds strange given the complexity of this system. However it has a lot of minimalist concepts where appropriate, such as use of pure acoustic slopes where it can work.
Usually when I'm not happy, I can trace it to a speaker issue requiring more work. I always was impressed by John Wright of TDL who tested all his designs over a long period. Once he had them good, he would only make crossover changes at three to four month intervals. Only when he stopped revising did he release a design for the market. I think most designs are released for too soon to market, because of the pressure of these money grubbing years.
I follow the same basic plan, except I don't release to market.
Even small speaker problems interact in a most unfortunate way with room problems.
I'm listening to Angela Hewitt at her Fazoli piano in two channel bypass mode right now.
Signal is as pure as possible. CD player decoded by RME Fireface 800. Analog to Rotel pre/pro in by pass. Then to the electronic crossovers amps and two front speakers.
Sounds like she is playing right in front of me in a plane behind the TV screen.
I suspect I'm hearing very little difference to the sound at the recording venue. It really does sound like a piano does in real life, so I don't have an urge to have a computer based system interfere, but that is just my view.