The binaries do exist. Just replicated using your exact same specs. You'll see that pak pulls and installs binaries. The reason yours did not work is you didn't register the correct PPM repository. Take a look at my initial command to see what I mean. Maybe not your preference but it works.

So yes, there is a simple (relatively speaking) approach for system-agnostic package installation from binaries via P3M. Many of your additional points are valid, specifically no command line equivalent to e.g. pixi or uv.

Have you checked out pak? pak’s default is to use the Posit package manager (P3M) and its full support of binaries for CRAN, including most major Linux distributions. The only small caveat is that, until recently, P3M did not provide arm64 Linux binaries (but now are available for select distros).