We give up perspective to avoid tone controls

You are right sometimes I wish I had some sort of tone control, as mentioned they have to be made right or you get muddy sound, would an eq be better? Maybe but I can put up with a bad recording rather than having to adjust constantly.I am sure there are systems worth a lot of money that make those bad(dull or bright) recordings sound even worse.I have a small amount of room treatment and it does help in my bright room.I guess the thought is its going to add or subtract from your system and add distortion, but if you  like tone control's and what they do for your system why not?

I am of the opinion and although this may seem bullish , we pay for our music and if we want to use tone controls then why not if it makes listening to them more pleasurable. Also some people of a certain age have quite a loss at the treble frequencies and a few decibels of eq. can make all the difference. I now only listen to music through very high quality headphones and a DAW that has lots of jitter busting software on it so is a very resolving system. The worst thing I find especially in solo piano recordings is that some notes are very much louder than others and it can be infuiating to listen to as when you hear the same work in concert this regulation anomaly is usualy absent. As an example I recently purchased a hi rez download of Murray Perahia playing Bach Paritias and two notes on the piano were really shouting at me and it was really annoying to the point that had I not the means to save it , it would have been wasted money.
As I am really into recording now and then I use on some recordings my Digital recording program Sequoia and using some very juditious Eq. on the file renders it a completely different experience it's as if Mr Perahia said to the piano tuner to sort out the loud notes and soften them.
Now I came from an era where tone controls were completely normal and one of the best ones was from Quad Electroacoustics and their method was gentle slopes which could make a great difference to a recording and this was many years before room tuning. I am not saying every pre amp should be issued with them but I am saying it is not an offence for some of them to have them.

When you really think about it everyone's hearing is different and can change from day to day or hour to hour depending on a huge variety of conditions both internal and external. I'm not so sure one needs to be a purist, maybe tone controles have there place?

It’s certainly a question worth revisiting; the assumption that tone controls in the signal path were not ’purist" has held since the early ’70s (as I remember it). As another poster noted, I was stunned at how much a box shop HT pre-pro with DSP cleaned up the subwoofer on a small system and now use an inexpensive DSP unit on the subs supplementing my main system. And agree that a lot of audiophile choices about gear are probably influenced by the house sound or voicing of specific pieces of gear, wire, etc.
What is out there in the market that is reasonably available? The Cello unit was well thought of at its time, but pricey. Pro gear? Parametric multi band eq?
I guess one assumption that continues to hold is that the system should be properly set up, "voiced" and left alone-- not messing with the choices (however questionable) that might have been made in the recording or mastering of a work. But, in that context, EQ could be used to set up the system, even if it isn’t user adjustable thereafter.
Is this easier to do in the digital domain? I know "all analog" buffs are wary of anything with the "D" word, but those who have embraced digital have already made the leap (or sold their souls).
Me- I am increasingly ambivalent about the purist approach, knowing how much gimmickry already goes into to most commercial recordings and how difficult it is to reproduce the illusion.
Many years ago, i had set up a half-assed rear channel system (long before surround sound) that relied on out of phase information (Hafler) and delay lines from a small processor. I used it with a pair of modest bookshelf speakers to supplement my Quad ESLs. When a very knowledgeable friend visited, he said "what is this? Turn it off." Then, after a few moments, ’ah, turn that on again." It worked on some material better than others.
Good topic, worth thinking about, since "we" haven’t changed or questioned our assumptions about this in decades.....

@erik_squires .. a timely post indeed.

One thing that is implicit in the culture of "high end audio" is the disdain for any sort of electronic equalization. The culture disdains the use of anything other than a volume control. Instead we attempt to change everything to avoid this. Speakers, speaker cables, amplifiers, and power cords. We'll shovel tens of thousands of dollars of gear in and out of our listening room to avoid them.

With so many good software DSP/EQ options these days I can't imagine why some folks wouldn't at least have a listen for themselves. I know quite a few audiophiles (including myself) who decided it was time to move past the disdain and give it a spin. I think Schiit, with the release their Loki tone control, also inspired many to move away from the old way of thinking about EQ.