The idea of a game over state being necessary for a video game is undisputed, but in an H game the priorities change from providing a video game experience, to providing a jerking off experience. Game overs makes you stop, load, repeat, which ironically is similar to just continuing as if the game over never happened most of the time to explore options. More over, most of the game over elements happen out of issues you likely voluntarily committed to yourself, which defeats the initial reason game overs existed, to learn from your mistakes. There's nothing core or essential about an H game needing game overs, unlike regular video games, it's an archaic design that hails back to the old generic H RPGs where you go to point A, fight a boss, lose to see H scene or win to progress the game. Versus an H game that gives freedom over picking to continue from a state at which 'bad' things happen, there's more creativity in allowing it for more degenerate H content as the character(s) have more experience in the long run for more dialogue and options towards the H scenes. Which is something we saw from this very H game no less, albeit very minor.
As for the QTE, or just key command input points, it doesn't actually matter since the combat is traditional turn based anyway, a proper QTE would actually slow the game down, and the inputs do change based on your arousal level when trying to escape making them actually raping you much more likely. The only issue is actually getting aroused in the first place I suppose.
