I am fully aware I'll draw out the hatred of many a person in this forum but I don't play ASCII roguelikes anymore, like I did back in the day. if I am able to create a free game that uses graphics I don't see why anyone else shouldn't. In that vein a roguelike for me nowadays has to be free, graphical and preferentially have mouse support too. This locks me away from some interesting titles, sure it does but I have no shortage of cool games to play that fit these requirements either.
There are a ton of libre resources to be used for roguelike development, but I do agree that coming up with new stuff to fit your game can be a pain if you don't have an artist helping out or if you're not a half-talented pixel artist yourself, at least. Anyways, repositories like this should be more than enough to create a typical roguelike, unless your setting is really very unique https://github.com/saniv/free-game-art
I will make an exception to ASCII games that look absolutely beautiful - to the level Ultima Regum seems to be getting at. I see people talking about how beautiful Brogue is but, really, I'm not impressed. Anyway, I'm not currently playing any ASCII game even though RL is the video-game genre I'm most interested in.
Computers have been handling graphics quite well for almost 40 years or so now, the programming overhead is negligible and if a developer's reason for creating an ASCII is that then he probably doesn't know very well what he is doing (which is fine for a starting programmer). Creating a good-looking ASCII game is probably a lot harder than creating a good-looking game with art assets, when you boil it down to time consumed in developing a typical roguelike.
And yes, non-ASCII games can still be roguelikes, as are all of the roguelites out there. Would you say Dungeon Crawl is not a roguelike? Of course you wouldn't but nowadays there must be a ton of players who only play WebTiles and have no idea there is even an ASCII mode for the game.
Also you're only 42? More than enough time to put at least 4 new great roguelikes out there, starting now
good luck with your project!