

- You’re clueless about how cargo itself wraps/calls rustc. And how other build systems are doing the same, including the one literally mentioned in OP. “Because having rustc as a standard tool is not there yet” is a completely meaningless nonsensical sentence. Neither is rustc lacking in any way, nor is cargo imposing any sort of hard requirement on itself.
- You’re clueless about how cargo works. How it natively supports both vendoring (with a single command) and multiple other ways of source replacement.
- You’re clueless about the fact that rust statically links std by default, and the fact that the ABI is not stable between major rust versions which is a deliberate choice. And thus, the attempt to draw parallels with “C repo and make” is yet another indicator of your cluelessness.
There is more. But I don’t have the time untangle the webs of cluelessness in your comments.

Incorrect. Vendoring done right (via
replace-with, as done bycargo vendor) is not mutually exclusive with the rest of the tooling. You can have both.