Eberron? Not really, and certainly not in comparison with Forgotten Realms, which I believe is Hussar's point. Most NPCs listed in the original ECS rarely break level 10, with exceptions such as your typical Dragonmarked House Baron (e.g. Merrix d'Cannith). Most NPCs listed actually do have NPC class levels. This intentional design approach is apparently worth writing about, as Sean K Reynolds discusses this fact about Eberron in
this old article. Even low-level NPCs are further toned-down in Eberron, as class levels are regarded as rare and exceptional.
There are only a few named NPCs off the top of my head that I can recall having high levels (15+) in Eberron: Vol, Great Druid Oalian (an awakened greatpine), the Keeper of the Flame Jaelin Daran (but only when she's in Flamekeep), and the Twin Rulers of Aerenal. As you may have noticed, these high level characters almost overwhelmingly tend to be geographically restricted. The Twins aren't going to leave Aerenal. Oalian can't leave Greenheart; he's a tree. Jaelin's high levels are only within Flamekeep, and she's a level 3 cleric everywhere else. None of these characters exceed level 20.
Can you honestly say the same about Forgotten Realms in 3e? It's laughable to claim that they are even remotely comparable. There's probably more characters in Forgotten Realms who exceed level 20 than there are in Eberron who exceed level 10. That's the sort of thing that Hussar is talking about.