apt-get is still the golden standard for installing apps on Linux because of its dependency resolution system, and being able to "sudo apt-get install <package>" is a core use-case for end-users (i.e. students who are learning how to use Linux / code for the first time).
Disclaimer: I work at Google, but not on Chrome OS.
Genuinely asking, what makes apt-get that much better than other package managers? Outside of Slackware I think good dependency resolution is pretty much universal at this point, and I can't say I've ever noticed any major problems with pacman, for instance.
Windows has a lot of users just because they're familiar with it.
The same goes for Debian derivatives. A lot of people's first Linux distro is Ubuntu, so they get familiar with apt and don't have a compelling reason to use anything else.
I'm a perfect example. The second package-manager I really interacted with was Alpine's "apk", and that's only because I've been working with Docker pretty extensively over the last year.
It not APT itself, but the policies, tooling and practices around creating and installing packages.
A lot of work is done to ensure smooth upgrades, or prevent packages from breaking each other by overwriting files, breaking configurations, changing ownership of some files or directories and so on.
Apt-get got there first. Debian does a pretty good job of trying to make upgrades work (which isn't really an apt thing, plenty of apt based distributions don't actually care to make upgrades work).
It's been a while, but my understanding is redhat figured out dependency resolution too, though.
Depends on what you mean by "figured out". Yum was capable of dependency resolution 15 years ago, maybe more, but was unbearably slow compared to apt-get. Maybe dnf solved that, maybe yum is faster now, I don't know, I switched to Debian more than a decade ago and didn't have a reason to retest RH since.
Even on the slowest systems I still have access to (64MB VPS, RasPi 1), apt-get is reasonably quick and responsive.
It's been a while since I've used it but yum used to tie up my machine pretty badly on significant upgrades. After reboot it could take hours to finish applying the upgrade, during which time the machine was usable. Apt has never given me that sort of trouble.
Maybe 15, but I do recall using redhat in 1998 and getting things like you can't install foobar.rpm because it needs /usr/lib/libsomethingcool.so.4 and then plugging in that file name to rpmfind.net to figure out what package I needed (maybe it didn't need to be that hard, but it wasn't obvious that it could be easier)
Disclaimer: I work at Google, but not on Chrome OS.