"Making everything optional" is for the embedded space.
As for general purpose processors, RISC-V has always had the idea of profiles (mandatory set of extensions). Just look at the G extension, which mandated floating point, multiply/division, atomics, ... things that you expect to see on user-facing general-purpose processors.
> the belated admission that maybe we shouldn't have everything as optional extras
That's why I disagree with the above claim.
(1) The optionality is a feature of RISC-V and it allows RISC-V to shine on different ecosystems. The desktop isn't everything.
(2) RISC-V has always addressed the fear of fragmentation on the desktop by using profiles.