Who Tried Power Conditioners Over The Years and No Longer Use Them Today, Any Why?

Been thinking back to when I started in Audio and how good the system sounded with no power conditioners or fancy power cords. Then in the '90s slowly they both became a huge profit market for stores and manufacturers of them. If you used one on front end gear only or whole systems I will be interested in your real-world experience you could share with us all. I have a few so I am not against them, but I do at times have questions. 
" But profits come from satisfying consumer demand."

No Miller.  Profits come from stimulating it.

You've said it Miller:   "Selective memory nostalgia", is when you think you hear a difference after adding a passive component that you've paid a lot of money for, and then it gets locked in by the warm feeling generated by the apparently positive response to your wise spending.  We all have the urge to feel happy whether or not there is anything to be happy about.

As far as passive power cords are concerned, all will do the same job as long as they can pass all the current demanded without high resistance.

Power conditioners can be useful if they can actively remove noise and other unwanted artifacts from the line.

Plugging my amp directly to the outlet (instead of three different high quality multiplugs I’d sampled) made my system more dynamic, rich, and full-sounding. It wasn’t a figment of my aural imagination…it was clear, evident, and palpable. I gave it time between configurations, and ended right back to just plugging straight in. 
Then, I replaced the cheapo outlet with a Hubbell oulet, and there was an additional improvement (although that might have attributed simply to the fixture holding the plug more firmly/increased contact). 
I still use a Furman multi for the rest of my components, for convenience. 
Many residential and commercial spaces apparently do not require power conditioning. My colleagues here in the department of electrical engineering and computer science measured the voltage in our house and within our home network. They even brought some expensive retail conditioners to test and they (and me using my ears!) - we found no measurable or significant differences. I will post their results if there is interest. There are no problems or issues here - thus, I believe that those who suggest that we can all benefit from power conditioning are wrong.
All circuits in my house are 20amp as it was built. I have all units plugged into a Mc MP500 and use my own built power cords of Furutec components. I like having the ability to unplug just the PC when experiencing lightning storms which we have frequently in the spring and fall. 
I bought an Audence AR-6 a couple of houses ago and it got rid of the noise in the power.  The last house, the power was cleaner and I pulled it from the system.  We just moved again and the power here is really flaky so it’s back in the system.

All the best.