It's definitely not any more retro than platformers are. Rouge was one of the first computer video games though so the play style was designed for VTEs (the authors went on to write curses, a popular VTE GUI library) and doesn't really need much beyond that.
Pokemon Dungeons (I think that's the name) was a rouge-like from Nintendo for the NDS and was played in a a cell playfield just like the other rougelikes. I guess it helps that Pokemon was a GB game and the hardware was meant for that kind of thing so most of the fanbase is used to it.
But yeah I wouldn't call rouge-likes retro anymore than Mario or Pokemon is. Rouge itself maybe, it's very primitive. Nethack is still developed though and new rouge-likes are still written.
It's a very distinct game genre that focuses on careful thought and strategy but also has RPG elements. You really should try one if you haven't. I wasn't really allowed to play Nethack when I was a kid due to the "witchcraft" thing but got into it as a teenager. It's a very good game and will fit nicely in your tmux session.