I think it’s mostly a branding issue rather than any cultural failure to expand people’s horizons. DnD was the first one, and it’s still one of the biggest. If I walk into any old Barnes and Noble, I can get DnD, I can get Pathfinder, I can maybe get Shadowrun, but I’m not gonna see Fiasco, or Burning Wheel, or anything not made by a big company that can afford advertising and big publishing deals. The ttrpg environment is in a weird phase right now; it’s been riding high on the tabletop industry exploding in the past few years, but it’s still a niche market. There are thousands of options right now, but the audience (in cultural terms) is still tiny.
I think if you wanted to make a big effort to pull people in who have never even thought about ttrpgs before, you’re going to need something like kitchen-sink fantasy or kitchen-sink adjacent. I think you could easily subvert expectations by selling an adventure fantasy rpg and then make all the rules about character drama instead of fighting, but it would be bold to try selling an “intro to rpgs” that is a different genre. Not saying there’s anything wrong with that, hell, it would be amazing if a new rpg exploded onto the scene as both an intro to rpgs and something distinctly not DnD, because I think changing the public perception of ttrpgs is something that’s going to have to happen externally onto pop culture as oppose to waiting for it to catch up (how many Critical Role level shows plays something other than DnD?)