Many of us developers will remember when XFree86 changed it’s licence with the release of 4.3.something (officialy with 4.4). When Debian decided to stay with the last version that still had the old licence and backport drivers selectively that do not have the new licence terms (which were most of them IIRC. I remember Alan Cox explicitely not agreeing to have his code’s licence changed)
Noone ever noticed Xfree86.org releasing 4.5, did you?
Xfree86.org has gone entirely off the FLOSS radar.
In retrospect, the project killed itself by changing their licence, putting in some clauses many users, developers or maintainers found inacceptable. (FSF says the licence is incompatible with the GPL, i.e. a GPL program cannot use the xlibs from xfree86.org)
Everybody is using X.org now. (well, we at Debian are still shipping xfree86 only in sarge, but we are only providing security updates for it anyway, and we have an updated version to which the old licence still applies).
And I actually think that it was a good thing:
X development has picked up a lot since back then, I have the impression that more people are actually working on it than before. (But that may also be due to the joint efforts of GNOME and KDE at freedesktop.org)
With X.org we’ve seen a couple of new developments that have long been requested for Linux, including the famous Screenshots with real transparency and real shadows by Keith Packard which made users scream for X.org at the poor Debian maintainers… (although performance depends very much on your driver, and maybe stability and other archs are more important…)
One of the bigger things for developers - which will happen with the 7.0 according to schedule - is the modularization and autotoolization of X.org sourcecode, which should make maintaining them a lot easier apparently. Yay!