I just ran "pkg install llvm50" on FreeBSD. Easy, quick, and noninvasive; it's not like installing another compiler is going to trash your system, you still have to take action to use it in place of the default. Likewise on Linux, you've always been able to install multiple compilers, and I've never had a problem with that in the two decades I've been doing it.
I can see containers are sometimes useful and/or a convenience, but you're right it is currently some weird cargo-cult. I don't find it that lightweight either; it can waste serious amounts of space storing all the different images and intermediate states in Dockerfiles. At least on FreeBSD I can use jails with ZFS snapshots (and dataset compression) to keep space wastage to a minimum, and have it quickly freed when I'm done with them without any extra effort.
I can see containers are sometimes useful and/or a convenience, but you're right it is currently some weird cargo-cult. I don't find it that lightweight either; it can waste serious amounts of space storing all the different images and intermediate states in Dockerfiles. At least on FreeBSD I can use jails with ZFS snapshots (and dataset compression) to keep space wastage to a minimum, and have it quickly freed when I'm done with them without any extra effort.