I've moved away from K/Ubuntu to Sabayon because I liked the rolling release nature of a Gentoo based distro and hated the "Forced Upgrade" nature of Ubuntu (ie. once the repos for your version are no longer supported, you have to upgrade the whole system, which may or may not work), but I'm not by any stretch of the imagination a linux wiz. I'm just an end user with enough know how to create a symlink, which I've had to do on occasion to statisfy versioning requirements of one or two programs
My question is, why bother using versioning? I mean yes update lib's and such, and by all means refer to the version number in tarballs and package managers, but why not use the same name once installed eg 'libxyz1.2' -> 'libxyz1.3' when installed would just be 'libxyz'. Would this not solve the compatability issue when a program is asking for a particular lib but can only find the updated version? This would also mean that all updates would need to be backward compatible with its older versions.
2) How do you know which is which when there happens to be improvements in the API as well as extra edges added in without versioning? A change from 1.0 to 2.0 may well radically change things. A change from 1.2 to 1.4 may add an extra function or change how a current function goes about doing things. Just using the same name on the library isn't a good idea- if you presume a 1.4 edge and 1.2 had slightly differing rules for usage, you can end up with a crashing app- and no idea as to WHY.
In the end, your idea, while it seems "obvious", isn't such a hot idea after all.