I don't think MDN is going to go anywhere anytime soon. I remember someone on Twitter saying that there are enough people from other organizations who had already been involved in the MDN docs before the lay-offs at Mozilla and that these people will likely stay involved.
Case in point: Both the MDN Github repos and the MDN docs (or at least all the pages I bothered to look at) show very recent activity:
Now someone needs to take over MDN . By far the best JavaScript documentation