Never implied that they couldn't, just using context you put in the game to reinforce a point.
It's neither difficult nor not difficult. It really depends on what kind of crowd you aim to please within the NTR fandom. Using tropes is always an effective enough way to make a good NTR game, it's just a matter of who finds what "good." A lot of people love mind control, a lot don't, alot of people love the typical loser guy with the small dick getting cucked by the gigachad alpha with the massive cock, a lot don't. One crowd will be easy to please with one trope while simultaneously being difficult to please others who don't like it.
For me personally, I don't need an elaborately woven tale with tons of exposition to evoke more feelings for the characters involved. A lot of times, porn game creators suck at doing it and end up making a story so long and drawn out that I end up losing interest before it even gets to anything good. I'm a fairly simple man with simple tastes, I can simply get by with a small dick loser who gets cucked by a gigachad alpha with an impossibly massive dick. Make a decent enough narrative out of it while adding a good amount tension induced moments to build things up and I'm golden. I don't want the narrator telling me that the Alphaman is putting his dick inside the pussy and describing the texture and sound in detail, just give me the visuals. It's not a damn book.