I think it's the mainstream belief that power conditioners don't make a difference that makes it a very niche product and why it continues to be so expensive.
The Sound Application devices are hand built and outside of recording studios, no one really knows about it. I only came to know about it through a friend, and I went in to listen to his system quite skeptical but his system sounded good. At first I assumed it was his gear. They were CJ GAT/ART with ASI Diamond Tango speakers with a 2 box EMM Labs as source. But removing just one of the conditioners changed the soundstage completely, it was startling. If bias is going to affect your judgement, I should not have heard any differences.
I can see why studios continue to invest in these conditioners.