If you're lucky enough to get into a ward that has a couple of very large and active FCs that have members that like to chase each other around the ward, it can be lively. The ward my personal house is in had bursts of activity for a few months thanks to a very large FC that also had a house there but that FC is no longer as active so I rarely see anyone now outside of one of my neighbors when we occasionally meet at the MB. Since the start of the expansion, I'd had maybe 5 players randomly show up at my house when I was there (no real way of knowing how many might have been by when I wasn't there though I do see the like count in my message book increase along with getting the occasional message).
Our FC house can be active with members coming and going at times, or we're gathering for map parties/mount farming, but that's at the FC house. The members aren't roaming around the ward so if you're on the far side of the ward you'd never know we were there.
I think people forget what makes their own real life neighborhoods feel active. People outside for an hour or two doing their yard work, children playing, general traffic as people are out on errands or going to/from work.
We lack those things in game. Gardening only takes about 5 minutes tops and most house owners don't bother with it. There are no children for our characters. We don't need to travel through the ward - we port to our houses, and port away from them unless we're going to a MB, Summoning Bell or merchant in the merchant area. If we're at our house, we're far more likely to be in it where we can't be seen instead wandering around outside.
If my house plot was instanced, I doubt I'd notice the difference.
SE feels like they're trying to address the emptiness with the Firmament. We see NPCs scattered all over and when we get close, we can see small snatches of dialog in the floating speech bubbles. But in a way, I think that just emphasize the emptiness even more because we can't interact with those NPCs. They're decorative elements that start being mentally blanked out after a while.