The compile repository should just contain the absolute bare minimum of primops and what not, regular libraries should do the rest. Yes there should be a batteries-included starter pack, and it can be bigger than most standard libraries even, but it should be maintained separately.
Ironically, C, with it's terrible stdlib, gets this right. Neither GCC or Clang is in the business of maintaining libcs. C does this for Conway's law reasons with kernel vs compiler competing for ownership, but still, it's a good result.
People squirm at the thought of this. I think the issue is not that this is inherently bad UX, but that Cargo/Cabal/etc. are simply too shitty. I think people's expectations of those tools is too low, and if those are fixed, this problems with this will evaporate.