You have to find the right level of grind. Grind is used to get players attached to a game. If you invest time, you getting attached to the game, because your mind tells you "I played for so many hours, I can't give up now else everything would be wasted!". And every now and then you get a reward of a new scene and this triggers other levels in your brain. Boom, more attachment.
The grind in this game is okish, but not to much. Also this is a incest theme. Convincing a family to have sex and feel good with it needs some time. If it would be a go to the club and bang some random girl game, then yes the grind would be to much.
What you're highlighting is exactly my issue: sunk-cost fallacy is a lazy way to drive player engagement (and a boring way for me as a player). It always leads to unnecessarily bloated experiences that could easily be trimmed down and be better as a result because the experience would become more focused on the core aspects.
I don't mind games that take their time if the writing and developments justify the time it takes. One I love like that is
Long Live the Princess where getting to the sister character is very long and tricky, BUT ! Along the way you get an engaging magic-murder-mystery story and get to uncover more about that sister. There's also a lesbian you can turn Bi or straight if you want, entirely as side content, and it also takes time to develop, but each scene tends to be different, you're progressing a storyline, not repeating an action for a nebulous stat increase.
There's stats grind, and it takes a while to get them to the max and unlock everything, but it doesn't matter because you're experiencing scenes and story-moments along the way. This games strikes the right balance of porn and compelling storytelling for me. Nothing too fancy, but still some nice twists and layered characters to learn about (like I said, nothing too fancy, but it's miles above most of the competition)
Here in The Manor, all I'm doing is spying on characters, perving a bit on them and playing tag all to raise the stats and unlock the scenes.
There's not really any engaging story going on in this phase, it's mindless grind. And even when I unlock scenes, it doesn't feel earned (neither from a narrative standpoint, nor from a gameplay standpoint).
EDIT: To further explain the previous point in less words: There's no "AH HA !" moment, it's all "FINALLY.", if that makes sense
My go-to example for a well balanced game with this kind of grind is
Summer Memories. The story is nothing special, in fact it has a lot in common with the setup from Bones' Tales: The Manor: "Young man gets in house with 3 women, 2 young, 1 older, sexy time ensues".
But the unlocks are constant, you always have something new gameplay-wise to build towards with the currency you get, and by upgrading the character, you unlock new scenes because the way you get currency is through interaction with the family members.
Even without talking about the porn content itself (which I find excellent), the core gameplay loop is something you could release as a full indie game without the porn and I wouldn't bat an eye, it's very solid and well balanced with a variety of ways to progress.
That's not something I would say of The Manor unfortunately.
There's no decision making when you're grinding in this game, it's a very rigid set of things you have to do to raise the stats and that's it.
I'm sure the H-scenes in The Manor are good, but the game as a package I find lacking unfortunately.
And it's made worse by the fact that I have to wait so long to get to the H-scenes for no good reason (because nothing changes between my actions that raise Lust/Guilt/Trust, I'm just repeating the same think until it unlocks the new part, after which I'll repeat the process)
