It's outrageous that we came to this.
Everything else does not matter: if it's not a game that requires internet connection for a good reason (micro transactions and license check are NOT good reasons, it's a game), then the game should not require internet connection.
Additionally, for multi-player games, if they have a single player mode, same thing! I already cannot play multi-player, I don't have a working internet connection!
It's sad that enough people keep buying shit for these companies to keep getting away with this.
Since you like roguelikes, I'll have to propose Tales of Maj'Eyal.
I wrote a post about it not long ago here where you can read abit more info.