Mir and Wayland both use EGL. They are both essentially what Xegl might have become if the appropriate resources were attributed to it. Xegl was dumped because a consensus was reached in the xorg community at the time that the current display server with AIGLX would be fine. They did not want to rewrite a X display server from scratch. Without the support of the majority of the xorg community, which was necessary for such an endeavor, the project just died out.
And there was a schism focusing on that XGL was developed in house, "behind closed doors", at Novell by David Reveman (who now works at Google). The majority of which came from Red Hat who offered and wrote AIGLX. Was there blatant bullying? Of course not and I never suggested such. But was there some jealously and collision of egos? Yes.