"Theres so many times I wondered in our effort for the holy grail if we might be making it worse..."
All components are isolated out of the box to some extent. I think further isolation can only help, not hurt, but in many cases it may make no discernable difference, so you have to be level headed about how to go about it. Its just a safe thing to do.
IS there an an example out there of where more isolation is worse?
Looking at the posters system pics, the thing that catches my attention from an isolation perspective are those monster amps. Amps with high power transformers emit EM fields that can induce noise in other low level electronics, so the physical separation of power amp from other components is key.
Also, I prefer to keep my components low to the floor rather than high up on elevated stands to minimize impact of vinrations trans mitted through the floor. MY stuff sits on a $30 (second hand) 80 pound heavy solid oak coffee table/bench that itself sits on a solid concrete floor/foundation. The phono step up device is wrapped in mu-metal for needed additional EM isolation. Pre-amp and step up device are located as far away from the power amp and other nearby transformers as my setup allows. I"ve found these simple cost-effective precautions to be very effective!