I have no idea if the VPI tonearm is complex or not, or if it sounds good, but I do know that the 3D process allows for much more complex structures than casting or machining would allow. I also know, that after a given production, 3D printing is less economical. That production point depends on the cost of the tooling or molds required for other processes. However, that tooling or mold is required whether you build 10 or 10 thousand and can be prohibatively expensive to prototype, which is really the purpose of 3d printing, not mass production, at least yet. But, when you can tweak a design, and have a working prototype in a day, for little expense relatively, that allows a designer to try various options in something resembling their final form.
I just dont get why anyone would be down on Harry for building and selling turnables and arms when he could just as easily be buying stuff from China or making some other widget for Walmart to sell. Its his money, he takes all the risk, and is entitled to whatever profit he can derive. if you think you can do better, then take your own money, roll the dice and have at it.