There is work on this. This can be done with https://julialang.github.io/PackageCompiler.jl/dev/, but so far only to a rather large binary / “bundle”
IIUC, In principle it should be possible to do much better if you knew for sure at compile time which methods you would need to dispatch to for the data you ultimately want to run on.
The reason why we can't distribute precompiled .ji files at a package level is because of the way the package resolver works. It depends on the exact versions of dependencies of every package - and even for the same version of an end-user package, there can be slightly different versions of the dependencies installed depending on constraints imposed by other packages.
One major improvement coming in 1.6 is multi-threaded precompilation, and it will leverage all the cores you have.