I haven't seen any developer say that will be the case with EU4. I've only seen developers confirm what we all know, that it's not the case with current games.
Despite fanboy assertions that it will be the case with EU4, developers actually seem quite careful about NOT saying that will be the case in EU4. In fact there have been several developer comments about features in Steamworks, the API, and multiplayer, that sound like the Steam is going to be more integrated into EU4, meaning it might not be able to run in an offline mode, at all. They may not go full DRM in EU4 (though I haven't even seen anything definitive about DRM, either), but I'm guessing the push for Steam has as much or more to do with taking advantage of Steam "features" as it does with cutting out alternative delivery systems.
No?
You only need internet to install and patch. Just the same as gg.
Albeit talking about March of the Eagles, but that game too will be Steam-only.