...and enabled by default. Especially since portage BINPKG_COMPRESS can be set to lzip, what makes a great sense on multi-core == popular machines. (switching from xz to lzip [=plzip] quicken "quickpkg rust" from 2m to 40s on 4-core AMD)
The pigz/pbzip2/lbzip2 symlink hack relies on the fact that bzip2/gzip is installed to /bin, so we can make an extra symlink in /usr/bin. This can't really happen when the reference archiver is in /usr/bin. You can create a symlink in /usr/local/bin locally for it, I suppose. That said, you don't want to use parallel xz or lzip. It splits the compressed file into ${jobs} parts reducing the compression ratio.
Having _only_ app-arch/plzip works like magick for me :-) (I wrote how many times faster it is) What about !app-arch/lzip if +symlink is set?
I wonder if we could revisit this now we have app-alternatives/.
Right! :-) Just like with: app-alternatives/gzip USE="pigz (split-usr) -reference" app-alternatives/bzip2 USE="lbzip2 (split-usr) -pbzip2 -reference" (works for me)