I might be wrong, but I guess nowadays most users do not download software from e.g.
sourceforge and use it - they get the software from the distribution. In other words: if e.g.
X.org releases a new version of X today, users will only start to use it when the next Fedora,
Ubuntu or SuSE is released with the new X. Also, if the current Fedora, Ubuntu or SuSE
includes three different versions of X, the maintainance load on the X developers is three
times bigger because they get bugs from three different releases (of course, the bugs may be
the same, but they still need to test the fixes). So I think it makes sense to harmonize