I just tried to copy a folder of concentric radius circles to a different location (different centerpoint) in Google Earth Pro & quickly discovered this does not work. Is there anyway to transpose (I guess) a folder of coordinates/shapes easily? ...
As far as I know, your concentric circles are represented by polygons in a kml file. The coordinates of the vertices of the edges approximating the circles are given in absolute lat/lon, not relative to some circle center. The only way to change the location of the circles would be to edit the coordinates of every vertex.
If circles are your primary concern, there are a number of circle generator tools for kml available on the web. I can't recommend a specific one, since I haven't tried any of them.
If you want a more general shift capability, this post describes a program that appears to take a kml file, finds all the coordinate tags, and applies a shift to them. I haven't tried it, so let us know if it works for you.
This post on gis.stackexchange.com explains how to do the shift with gdal tools.