G was just a shortform to bundle commen extentions, it was never defined by the foundation as 'the base ISA for linux'. That was just what the first released version of RISC-V spec had in it.

I would assume that the V,B,J and possibly P extentions will all end up in the most used linux profile.

However I think the RV64GC will still be the relevant fallback that most distros will over to cover a very large range of chips.