I wouldn't say 10,000 concurrent players on a single server, out of a game that had millions (even just in the west, if we're discounting the Asian players who wouldn't necessarily play on an English language nostalgia server), is a particularly noteworthy number. The guy's statement is elitist (the traditional meaning of elitist, not in the sense of opposing casual) and condescending, but you can be sure that the bean counters at the behemoth that is Blizzard won't shed a single tear over 10,000 potential nostalgia subs. Even if subs are low now, they're still the gorilla, and they may even be willingly allowing WoW to wither away, now that they have other ventures to turn a profit on (Hearthstone, Overwatch, Heroes of the Storm).
I honestly think he's kind of right. I sure as hell don't want to go back to Vanilla WoW, where 18 of the 27 talent trees aren't just sub-optimal in PvE, but some are downright broken. And then there's the extremely limited content. I sure as hell don't want to go back to farming the same 2 or 5 daily heroics just to gear up to do a raid once a week; and that's in WotLK, where I had the most fun of any of my characters as a tree waddling around healing things. Vanilla had even less to do. This is, incidentally, the same problem I have with P99: what's left to do once you hit max level? And that's given they're at Velious, two expansions in (and Velious at least had some tiered/gated content to progress through).
At least Dalaya goes as far as PoP, where AAs give you a personal reward for helping friends out with things you don't otherwise benefit from (you can only farm the same content, which drops nothing for you, out of sheer friendship before it gets rote). Whether or not it is still Enough Content, or instead goes too far with the tiered raiding, given the low population, I can't yet say, being only new to the server myself.