Can backpack solve the 'basement' problem?

I don’t think Backpack, by itself, would be a solution for the “basement” problem. All the libraries that used “basement” would have to remain “indefinite” in the Backpack sense and depend on a signature instead. We would only commit to an implementation in executables (and test suites). So we’re back to a big coordination problem. And it would be difficult for participants to agree from the beginning because, when starting to depend on a library like “basement”, one doesn’t expect for it to become unmaintained! I believe Backpack makes more sense when multiple instantiations of some library are planned from the beginning. But in the “basement” case, we need something like a way to “override” packages while the dependencies slowly adapt across the ecosystem.