Text based games are not obsolete - the combination of low costs¹ and broad possibilities² make it a perennial tool in the indie developers' toolbox.
AI has really taken a bite out of Interactive Fiction³, but I recommend you look at past winners of XYZZY awards for inspiration into what is possible with text alone (my favorite is Counterfeit Monkey- a game about fighting tyranny with wordplay.) If you want to see something more mainstream (and profitable) Choice of Games makes a brisk trade in what are basically Visual Novels without the visual part.
And then you have things like Warsim (another commercial title,) which make use of textual menus (and ASCII illustrations⁴,) to run a strategy game (or RPG) without all that much actual literary text.
Dwarf Fortress, and Berlin-compliant⁵ rogue-likes are not so much text-based as ASCII-based, but the same benefits apply - the only thing you need to add a new monster to the game are the stats, and the mechanics it will use. Graphics wise, just pick a unique letter/color combination and it's in the game, no sprites/rag-dolls necessary.
P.S. finally, like redonihunter said above, you can browse this very site's thousands of text-based games for inspiration.
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(1) Text games don't need complicated art assets - illustrations and background music is as high as you ever need to go, and most of them don't even have that. The engines for text-based games are also orders of magnitude easier to both program and use.
(2) The player can use their imagination to visualize, well, anything you can imagine.
(3) A big draw of IF was that you could command the game in what looked a lot like natural language.
(4) Many of them procedurally generated for a minuscule fraction of the dev-time it would take to get 3d procedural pictures to look even passable.
(5) A copy of the 2008 Berlin Interpretation, hosted on roguebasin