There is no surprise in the quality of RBCD these days. Many have known this for 20+ years.
I wrote a piece on CD sound (on Audio Asylum in 2009) called "red book riddle solved". To my surprise, I was nearly laughed out of the barn. Letters to the editor (Robert Harley) proved no better, as he rejected my claims that CD was "all we needed *if* recorded at high-bit and properly dithered"..
What took so long. Well, things drilled into our heads -how good LP was, the "standard", according to Jon Valin and Michael Fremer.
Then confusion. New formats -SACD, DVD-A, now MQA - none were better than CD.
And it was never about "upsampling" either, as the best DACs produced didn’t need or use this.
Beyond the hype of LP (and new digital formats) what delayed people from finding out how great CD can be were (2) setbacks in digital playback.
One was the giving-up of R2R DACs. This decoding scheme, despite it’s (potential) errors in switching, is still the best way to convert D to A. High-end makers have been returning to this since 2011 and the results are very welcome.
The other unfortunate thing that happened was the switch to hard-disk and SSD sources. The first generation USB standard was a disaster.
All of this has been solved -even if data-connections and converters are still not absolutely perfect. So glad everyone (seems) to be on board !