Thoughts in passing:
I find it interesting that at the same time CD players are becoming more and more sophisticated, and more costly (two years ago, if someone had predicted that I would spend what I've spent on digital gear, I would have laughed them out of the house!), SACD players are becoming more affordable. I'd almost be willing to predict that the latter will also bottom out in cost, and then follow an upward path similar to that of CD players.
Regardless, it is obvious that big money must be spent truly to retrieve all that a CD can offer. I think a valid comparison can be made with analog, in which modern 'tables,
cartridges, phono amps,interconnects, etc., are capable of getting more out of old and new LPs than anyone would have imagined back in their heyday, but NOT inexpensively. This is to say that high end digital players are providing much better sound than could have been imagined in the first years of the CD's existence, but obviously for a price; and this is in addition to the improvements that have been made in the digital recording process itself.
SACD is not the "be all, end all" at the present time, regardless of what we are being told. As much as I want the format to work, however, there is too much music available on redbook CD for me to turn my back on it and concentrate on SACD, especially in view of the appalling dearth of music, that appeals to me, in the latter format.
Although I am an engineer (retired), my field of endeavor was not electronics, and I'm certainly not up to speed in the complexities of digital sound reproduction. That said, it seems to me that the "step" function of digital---as opposed to the "ramp" function (for lack of a better term) of analog---can never provide a true replication of the original event, regardless of sample rates, etc., unless said sample rates are infinitely high ("steps" infinitely small). The best we can presently hope for is synthesis of "ramps" from one "step" to the next("upsampling"/"oversampling"?). For many---trained musicians in particular---this is not good enough; it is considered electronically-produced sound. I am willing to accept it, especially in view of the tradeoffs between analog and digital. Regardless of what is said in favor of LPs, they start to degrade as soon as the shrink wrap is removed; they are relatively inconvenient; and I don't expect ever to see a big variety of modern recordings, of the music that appeals to me, in the analog format. A CD remains the same from day one, which can be considered good or bad (its detractors interpret this as "lousy sound forever"). With the sound I'm presently getting from my system, I can no longer agree with its detractors. So, until something better comes along, the CD, "super audio" or otherwise, will have to do.