I don't know if this is still the case, but for SBCL on Debian installing with apt-get would get you an incredibly outdated version, and all that common-lisp-controller nonsense. The standard advice was NOT to install with apt-get, but to install manually.

Usually apt-get doesn't feature the most recent up to date release, also you assume everyone uses a Debian derived distribution of Linux, bad assumption. I'm on openSUSE and I'm sure many are on Windows or Mac.

If you need the absolute most recent release of a language to write code in it, that in my opinion is a bad sign -- maybe it's still a bit new and evolving rapidly, if there's a runtime component it might be awkward to distribute to machines you want to run on, and setting the dev environment up becomes a little painful which can discourage others from contributing. Not a dealbreaker, especially if you're just experimenting or doing a small private project, but for anything serious I would be worried if I couldn't develop and run it with whatever version of a language is shipped with the major Linux distros.

I'm on about it being behind 2 or more major versions.

I meant "apt-get" or whatever else is used in your system - brew, yum, whatever.