Comment by HKH2

More than 20 years, with a single-core Pentium 4, it could take indeed something like 3 days of continuous compilation to compile an entire Gentoo distribution, in order to have a personal computer with every application that one might want.

However, already after the appearance of the first dual-core AMD Athlon64, 20 years ago, that time could be reduced to not much more than a half of day, while nowadays, with a decent desktop CPU from 5 years ago, most Gentoo packages can be compiled and installed in less than a minute.

There are only a few packages whose compilation and installation can take a noticeable time, of up to tens of minutes, depending on the chosen options and on the number of cores of the CPU, e.g. Firefox, LibreOffice, LLVM.

There is only a single package whose compilation may take ages unless you have an expensive CPU and enough memory per core: Google Chromium (including its derivatives that use the same code base).

I can effortlessly compile Debian packages on my phone.

With some limits of course. I can't compile Chromium even on my laptop. But most of stuff - I can.

Not Gentoo. The system I'm suggesting is one where you replace the linker with one which accepts a platform agnostic assembly code with similar semantics to C, and perhaps some additional tools for stack traversal to allow the implementation of garbage collected languages and exceptions. Compiling would be fast because the code you distribute would have already had optimisations applied to it in a pre-compilation step. It would also be automatic in the same way the present linker system is automatic.