Nobody is actively working on it now; the same can't be said for Wayland. Recently, it even hit a development low of all time. The only ones working on it are the ones getting paid to work on it, and even then, only those familiar with the codebase. Looking at the history, the only major changes are for Xwayland, and aren't at all often.

If (almost) all of the developers have abandoned something in favor of a newer piece of software that does the job better, I think it's sufficient to say that it's deprecated and unmaintained.