I'd say cultural differences are to blame.
The West likes to rail on inequalities and more than readily makes fun of its own sociopolitical systems. We like our video game politicians arrogant and corrupt, because it comforts certain confirmation biases we all entertain. The Candidate we Don't Like is an Ass, the Candidate We Like is a Saint.
On the other hand, there's a certain degree of social taboo that we refuse to go past. Consider the modern Leisure Suit Larry games' poor performances, as well as the fact that the "Porno Games" industry is next-to-nonexistent. Everyone knows about General Custer's Revenge and Rapelay, for instance, but there isn't much of anything else available, otherwise. I'd expect some people to mention Huniepop, but even this particular title's inclusion is debatable.
The short of it is that the average Western mind doesn't really consider Boob Physics or titillation to be inherently marketable notion.
Then, consider the fact that if you're enjoying games like DOAX, you're probably in the minority. Anime's grown to be as democratic as could be, but cutesy slice-of-life stuff with titillation or even raw fanservice ? la High School of the Dead aren't as culturally salient as you'd think, outside of enthusiast circles. Ask any rando which anime he likes, and chances are you'll either get a negation or a more mainstream answer. Naruto, for instance.
With that in mind, if the West produced a kinky sports sim, you'd end up with moral outrage on one side, indifference on the other, and a tiny, tiny core of gleeful supporters that would constitute a rather pusillanimous market.