Why redbook over SACD?

I disagree that SACD was never intended to be a mass market phenomenon.  Both SACD and DVD-A were launched with the intention of generating a market for multi channel and enhanced 2 channel.  Record companies were clearly licking their chops at the thought of new sales of their back catalog.  Streaming didn’t exist when these new formats were developed.

  It was a big shock to audio companies when the formats were greeted with mass apathy.  People had come to prioritize convenience over sound quality.

  The value of preserving deteriorating master tapes was real, but it was an afterthought, not the primary reason for developing DSD

Some will say that a well designed CD only transport is a no compromise device that when coupled with a high quality DAC will sound better than most SACD players.

Couple that with the relative scarcity and expense of SACDs, and relatively affordable options from companies like Jay's Audio, foregoing SACD playback may make a lot of sense.

In my case, I have the best of both worlds. My streamer includes a high quality Redbook transport and I use my Oppo player as a transport for SACDs, with DSD output to my DAC. Both CD and SACD sound fantastic. 

"There is a simple process to rip DSD off SACD using old Sony blu-ray players ": not sure how 'simple' the process is with a special player, but the last one I read was - at least to me - anything BUT simple. Need to google again, but would like to also have my collection of SACD ripped; but then, how do I get the ripped file to the 5.1 receiver (the external DACs I have a 2 channel only)?

but the last one I read was - at least to me - anything BUT simple. Need to google again, but would like to also have my collection of SACD ripped

I will say that it is not easy for folks who are NOT technically inclined. But I have a word document created AND the USB key with the required files for the Sony BD-59. If you purchase this player on eBay, reach out and I can send you the Word document and the files. This will need a PM, as I need to send attachments and what to include in the USB key.

I have ripped 150+ SACDs till date; the most recent ones, this past December.

Forgot to address this:

how do I get the ripped file to the 5.1 receiver (the external DACs I have a 2 channel only)?

Can you receiver decode DSD? If not, then you might have to use a DAC like Okto which can do multi-channel DSD.