the point is that the older R2R dacs have less issues and less fundamental flaws than modern delta sigma dacs.
You seem to have taken the statement and meaning, and put it on backwards.....
Up sampling was marketing spin It might work and it does (a bit, anyway).... but it was mostly thrown out there as a marketing thing.
People buy numbers, as that’s all they know about things, for the most part.
Eg, on black Friday I was in the stores (Eg best buy) and predominately people watching, and only vestigially shopping.
What I noticed is that they would always always always..buy a given 58" model of flat screen TV over any given 55" TV.
As the number 58" is bigger than 55".....
Bigger is better, right? Right?
Essentially, people bought dacs by the numbers, and quality was so far down on the list that it barely made any impact in any associated thinking.
Audio fanatics got served what was sold to the masses ----- The End.
Now, we can finally do discrete dacs well enough and economically enough...so R2R comes back with a vengeance, in the high end area of digital. Same for the FPGA versions of similar design and thinking as discrete R2R dacs.
The dual pathway now exists for digital. One high end and the other - pap for the masses. FYI, delta sigma dacs and upsampling is the pap for the masses part.
No big company is going to be making discrete R2R dacs any time soon. The volume required for good sales returns is not there.
Thus, small companies with their board modules and some efforts of internal designs of the same at the larger audiophile companies-- will be the norm for the foreseeable future.