No, sharding is a thing. I’d be in Valdrakken, along with my friends on the same realm, and we wouldn’t see each other unless we’re in a group together.
It’s even more noticeable in rp realms like Moon Guard. I walked around Stormwind when sharding was enabled and it would be just like Stormrage. But once they turned sharding off, it was overflowing with people.
A lot of people came back, and you can see that if you do a /who on larger guilds. When there were maybe 4 or 5 online on peak hours a month ago, there are 30-50 on at all times.
Of course if you compare it with the population back when WoW was a novelty, it dropped. But that’s not a fair comparison either. It’s been 17 years. People grow, people change, guilds die and new ones show up.
I’ve changed hobbies at least four times in the past 8 years. I’d be surprised if people stayed the same for even longer.
Edit to add: Population moves in stages, so to speak.
New content is added? They’ll do whatever it takes to be there. In this case, the Dragon Isles. That’s where people are right now.
Content draught after the new raid is done? Time to bring your level 60 alts to Valdrakken, or just stop playing until the new raid is out and go try out other games that just released.
New patch with new campaign? Back to the mains, time to resub and grind that gear.
And so on. No need to check leveling zones, the people are in Valdrakken, Obsidian Citadel or helping the Chef in Iskaara.