I agree. I'm optimistic about tools like Poetry
https://poetry.eustace.io/docs/basic-usage/ for solving this. Unfortunately Python predates the realization that good packaging tools were a thing that needs to be solved in the core language and not externally (Go, Rust, Node, etc. postdate this realization; C, Perl, Java, etc. also predate it).
The flip side is that decoupling the interpreter/compiler from the build system makes it more possible to write tools like Poetry (and, indeed, virtualenv) that explore new approaches to the problem. At my day job where we do hermetic in-house builds with no internet access and (ideally) everything built from checked-in sources, building C and Java and Python is straightforward, because we can just tell them to use our source tree for dependency discovery and nothing else, and we can set up CFLAGS / CLASSPATH / PYTHONPATH / etc. as needed. Building Go and Rust and Node is much more challenging, because idiomatic use of those languages requires using their build tools, which often want to do things like copy all their dependencies to a subdirectory or grab resources from the internet.
Of course, given that it's Python, there should be one - and preferably only one - obvious way to do it....