The (lack of any) build system is actually nice for flexibility. You can lay out files however you want, link together random object files without extra work, use your own weird dependency tracking, etc. Obviously it's not super easy to get started with compared to Rust et al. but choosing C++ in the first place implies some need for industrial grade features or unusual setup.

Sure, but JS has a myriad of choices too and yet we mostly agree on node_modules, package.json and npm (the repo). Big companies or weirdos are free to swap any of those with something else if they want but the little guys have something standardish if they don't want to inflict too much pain upon themselves.