From SUSE to Fedora now r' using libpng updated, and obviously geento based-copy (arch and Funtoo by example) always use the most up to date, since it is compiled on use time!. But they are the most widely used. Based on popularity its not the case! the project is for everyone,

... and
precisely the project is about something that kde.org assumed "old software"! vs kde4 for something new and, in fact the situation is quite ironic! so libpng 1.2.X must be suported too in primary opction even libpng 1.4 , and same for other cases like libexiv2 that differs in winbuntu releases

not in fact:

what do you mean? libpng 1.4 is already in many distributions

lest se the most based: (mother of all metadistro)
http://packages.debian.org/search?suite=all&arch=any&searchon=sourcenames&keywords=libpng  only 1.2 was! and libexiv  differs on oldstable to experimental

lest see the most popular and most used woldwide (note i hate winbuntu)
http://packages.ubuntu.com/search?searchon=sourcenames&keywords=libpng only 1.2.X was! and libexiv2 differs to natty from maverick to oneric http://packages.ubuntu.com/search?searchon=sourcenames&keywords=exiv2

Let's talk seriously. I understand that everyone here is up to last software and hav all for (both powerful machines as well as time to browse the Internet) but we must take into account two variables: debian is more liveCD distro that are built and are on the network, and winBuntu is the most widely used system today, and so more satirical is based on debian!.

This is not about preference but thinking that although the older software represent extra work, we all know that when something is older is better known and tested, and in some cases more prefered (like kde3 ironic!!!) this philosophy is carried by debian stability. Ubuntu combines this philosophy and tries to keep up. This filosophy take this project to named trinity, so..