[dTal]

Nowhere is it written that a system can only have one version of each library. Indeed, there is an entire system (soname) for resolving which of many versions of a library a binary should run with. There is no reason at all why you couldn't have a system where all the libraries are shipped in your application folder, but it uses the system ones where available. There's also no reason why every distro couldn't have every version of every library, and all software since ever would just work with the system version.

Distros screwed the pooch here.