I find it curious how incest all of a sudden became such a pervasive fetish. I get the taboo aspect of incest, and understand it really happens, and the intrigue, etc. etc.. But geez I myself can remember some really great times, some fabulously sexy situations that caused lifelong memories with women I wasn't related to. People like what people like, I get it. But there are many more sexy situations that can be written about that don't involve sex with relatives than those that do. There really are.
I think it all started off with the cougar/MILF category and even in films in the 90s (American Pie screams at me, with Stifler's mom). Before it used to be your best friend would sleep with your hot mom but then this taboo of you sleeping with the MILF grew out of it, so the bully fetish (being "cucked" or humiliated) is flipped were now the victim becomes the "hero" and gets the prize.
This category only works with hot MILFs that looks like they live in Beverly Hills and wear glamorous clothing, which is not going to be your typical suburban mom so this fantasy grew from that disconnect.
Milfy City being one of the first western games that had Linda who ticks the hot MILF (glam LA mom) but living in a uptown suburb were both parents own their own businesses and are wealthy, fitting this criteria. Over the years other devs have tried to make the "landlady" more grounded but this is where it starts getting weird for some people.
I feel if the main Li is super hot and not your typical looking mom but more of a MILF the taboo is still there but the "nerd" or "dork" gets the trophy that every other man obsesses over which is kind of the point of this taboo category. She can have the pick of the bunch but chooses her "tenant" over all others waiting in line for their chance.
Again, you're only beating your meat for a couple of mins and then reality sets in, you ain't putting much thought into it after. I think the problem comes when people try to make it too real.
I like the way Charlotte was written in this game, she ticks off most of what I would describe as "the MILF mom" and she shows affection like a mother (sometimes a bit too forced) but games were corruption is the main objective to lower the Li's inhibitions may also be where he feels it crosses the line.
In most games it's the MC that pervs on the landlady, but in games were the landlady pursues the MC, they tend to do much better because we all know teenage boys are horny 24/7 so being devious to turn someone who should be mentally stable and mature at their age is kind of a hard sell, you'll end up with games like A Wife and a Mother which won't see it's end until the year 4030.