I guess I researched my own answer. Apparently the DSD single bit enconding that SACD uses needs to be changed into a multi-bit PCM format for the DSP functions, such as EQ, Bass management, sound modes, etc, to process. So, whether it be an analog signal - which would have to go through an A to D to A conversion - or digital signal - that, at some point along the chain, needs to do a PCM conversion - some trade-offs will be on the table with SACD and modern day pre's and receivers, to take full advantage of DSP processing.
Of course, a Rives PARC in the analog domain is an option. But not a reasonably cost efficient option here for most mid-fi/entry hi-fi ambitious systems.
Of course, a Rives PARC in the analog domain is an option. But not a reasonably cost efficient option here for most mid-fi/entry hi-fi ambitious systems.