After spending many thousands of dollars on equipment over the years, I found it hard to believe that room treatment would improve the audio in my listening room significantly.
When people who had the most expensive rigs began to seriously tout "room treatment", I began to take notice; not because they had the most expensive rigs, but because they were the most serious "audiophiles". I know some people take the title "audiophile" as snobbish; I take it as descriptive.
If you haven't learned by now that logic is useless in HEA, just keep hanging around. "How can tacking some stuff on the wall give improvement over spending thousands on equipment?" That's not "logical".
Here's a link that lets you know how complex this subject really is;
http://pages.jh.edu/~virtlab/ray/acoustic.htm
Although I started out as being skeptical in regard to the degree of improvement that could be achieved through room treatment, now that I'm enjoying that improvement, I'm a leading proponent of room treatment.
Back to the specifics of holography; I would define it as a highly refined sound-stage. While we can get a good sound-stage with "mid-fi" we will not get "holography"; that requires HEA, but even here, the first stage of development is the "sound-stage".
If you have holography, "all" of your records will sound better.