It's not necessarily about it going out of style. Technology has just moved on.
I had one of these cameras (I think it was even the ZR850). I loved it, too. The quality was really decent, but when I upgraded my laptop, I lost my Firewire port. This was way back when Vista came out. I started scrounging for external Firewire adapters, and they just didn't exist.
It sounds like a total cop-out, but the truth is that as Mini-DV's popularity started to wane, Microsoft and Apple decided not to support it in their updates. Eventually, iMovie stopped supporting it, and so did Windows Movie Maker.
When I was on the phones in support, some of my least favorite calls were when people found their old DV camera and realized the tape had basically fused to the video head in their camera. They lost their footage and camera all at the same time.
