No doubt it is very complicated from both the engineering standpoint and the manufacturing standpoint. I actually did a little bit of reading last night to satisfy my curiosity. Before I started to read, I already was wondering whether anyone had ever made or tried to make cartridges using the same principles that apply to condenser microphones, except of course with the non-ridged diaphragm manipulated mechanically rather than by air pressure. So I did some searches for specifically that, and it turns out that there have been some forays into that approach, most notably (but not first) by Stax, starting in 1950, and eventually producing an electret phono pickup in the mid-70s. It was taken off the market just two years later, but there isn't enough information to discern the reason. Maybe it just didn't catch on the way they hoped. Some ambitious person could probably pick up right where Stax left off and make a killing building electret phono pickups.