Maybe invert that? Seems like everything "needs" to be online now. Either from DRM activation servers to always-online-for-telemetry-or-lootbox reasons.
Games are a mixed bag on that front nowadays, yeah, but GOG.com at least makes a point of only selling DRM-free games where the installer and all singleplayer content are guaranteed to work offline.
Not really anymore - most need online junk to do anything. Ubisoft is super guilty of shutting down some VM that probably costs $1 a month to host co-op or multiplayer match making for splinter cell games etc