Free Software: the road to a Universal bundle, a powerful app store, and world domination (Free Software Magazine)

gcc, binutils and related software are an example of completely relocatable software for POSIX systems. You can build a toolchain, install it to /usr/local/mygcc and afterward move it to ~/mygcc.

What's missing at this point is improving the various package managers to enable local unprivileged installation of packages that would support it. The hardest problem is resolving dependencies against two separate package databases (the system global packages and the user-installed packages). Ensuring consistency in all cases is not going to be easy.

Things seem to "just work" on Windows and OSX only because there's no dependency checking whatsoever! Users are required to take extra manual steps after an OS upgrade to ensure that 3rd party applications still work. The actual compatibility grid of proprietary OSes and versus proprietary applications would be quite scary if someone bothered to publish it.

Good support and documentation ensure that the users accept this without blaming the OS. Instead, we do a very poor job at the UI level, to the point that inexperienced users end up thinking that dependencies are there to interfere with easy software installation.