Take another example. Install LaTeX. It's something like 5GB. It's huge because it bundles enormous numbers of packages.
It seems like there are zillions of Linux packages > 100MB. What does all this crap do? Why does everything depend on everything?
Take another example. Node. Building it from scratch takes a pretty beefy machine and a lot of time. (It takes over 20 mins on my 6-core workstation with 32GB RAM). Most of that is building V8. When I worked on V8, we periodically spent some time trying to get build times under control, but the needle barely moved until it got going again. We spent months and months of effort, over years, splitting V8 into more source files and more directories and enforcing header discipline, but all of it made build times worse. Despite how cool V8 is, I feel embarrassed in retrospect that the build system is so bonkers.
Linux is like this everywhere. Monstrous and labyrinthine. It really is impossible to understand it all now.