But I don't know anyone, no matter how wealthy, using pure analog circuits for DPL II or DTS processing (DSP).
Agreed. But..., remember that when DPL processors first came out in the late '80s, early 90's, a lot of them were analog only. In fact, the analog ones way back then consistently outperformed the digital ones. Fosgate, Shure, etc, were repeatedly more highly reviewed, praised, and measured better than those from Pioneer, Yamaha, Sony, etc.