Wilson's "V-Material" (the element of the Pedestal that does the isolating) is a rubber compound of some sort. It's ability to provide isolation is limited by that fact, as are Sorbothane, Navcom, EAR Isotech, and all other rubber compounds. Rubber acts as a low-pass filter down to the not-very-low corner-frequency of approximately 10Hz (at best); Superior hi-fi requires a much lower frequency, as close to 1Hz as possible.
Wilson is just now getting into this field. Max Townshend (and others) having been working in the field for decades. Check out the Townshend Audio Seismic products for a path to advanced isolation.