If gains are 30% for tracking configurations versus stationary ones, it sounds more worthwhile for off grid types than grid tie types. Off grid types are dependent on the energy and 30% in gains makes it worthwhile, especially the part of the year where output is severely limited. But grid tie users would simply want to be focused for best performance at the peak usage hours and not muck with the array.
If someone opts for vacuum tube solar water heating, does it need to be tracked to get maximum output most of the time? PV technology isn't real practical to boost with mirrors, but vacuum tubes should love them. It would seem one could simply maximize output by mounting them at optimal pitch, yaw, and roll angles for wintertime, and supplementation via mirrors.