He has the sub-zero weather package, it includes what Tesla calls heated wipers, which is actually not a heated wiper, but in fact a heated strip at the bottom of the windshield where the wipers park. It does nothing to defrost the windshield beyond the bottom inch, but it does help a little bit with wipers freezing to the glass. Most likely his lack of issues on his MS have nothing to do with that feature, and are because he has working defroster vents, all current MS have them, and only the early ones tried to do with ones hidden under a screen, many of those have been retrofitted to the new vents too.
I had the "heated wipers" on my last vehicle, wasn't really all that useful, helped a bit, but I wasn't too upset that the MS I found doesn't have it.
My old Mercedes had an interesting rear defroster though, it was the same idea as the ones we're all familiar with, lines on the glass, however the lines were extremely fine, and much closer together, the result was that they were almost invisible, but worked quite effectively, still a bit too much distortion for a windshield, but I really liked them on the rear window.
