I'm far less excited about high resolution formats since I've owned M gear (of the upsampling/apodizing type). While it's very hard to do direct comparisons (as hi-res copies of the same recording usually undergo remastering, etc.) in general I'd say that overall I notice little to no difference in quality between RB and hi-res formats (although I only bother to buy 24/96 variants as there's not much point in taking up extra storage space on M system).

What does make a huge difference to my ears, in all formats, is the quality of the engineering and mastering - I have numerous wonderful RB recordings, many from the 70s, from highly skilled engineers like Tony Faulkner, which consistently sound better than badly engineered modern high-res recordings.

That said, in terms of convenience, I don't necessarily see why M chose not to, for example, implement promised 192 upgrades (presumably firmware only since they appear on product data sheets over 10 years ago?), not sure what harm it would do, and presumably would open them up to customers who don't necessarily do enough homework to understand they're not actually benefiting much from it (try telling the average camera enthusiast they don't want more megapixels, but they might want more dynamic range, better bit-depth, etc...)

Just my 2p worth.

HC: 861v4/ID40/LPS, DSP5000, DSP5000VC, DSP3100, SW1600, HD621, Oppo BDP-105, Sony VPL-HW55ES
2-Channel: Oppo BDP-105, TEAC VRDS-7/Trichord Clock 3/PSU, 551, Quad 303, Harbeth Compact 7ES-3, Kimber cables, Russ Andrews mains and supports.
Previous Meridian: 5000C, 5200SL, 7200.2, 6000, 562V.2, 568.2mm, 800v4, 808.2i, 818v2/v3, 861v8, 502