Your experience with NTR haters is just that, your experience, overall depending on the side of the wall that you are you will see different things, I'm kind of neutral on NTR, I never play to lose, but I don't like easy victories and the haters I have seen aren't what you say, I have seen patreons public posts being bombarded with haters messages, developers telling that the haters don't stop messaging them, one of the most recent example is the developer of goddess saga: darkness, ask the developer if you want and if you want a list of games that suffered too much hate for it then I can make one of you, I still remember many games being heavily attacked for it.
This is something that happens a lot.
And here is something that you should understand, Ann and Eric is part of the storyline, that part should never be avoidable. It's what motivates the story, of course on the sisters case you are right, it should be avoidable based on choices and actions. Even more it's wrong to call that NTR, that the mother of the character gets a boyfriend.
But the main point is the following, what you are asking is exactly the opposite of what I think, you see the only thing I'm asking is for a challenge and difficulty that I can overcome, while what you ask is to absolutely separate them and make them into routes. The funny thing is that what I ask can actually give you the game you want, but what you ask is impossible to give it to me:
-If you divide the game in paths, it is based on direct options/choices, you kind of killed all the interaction you can have in the game and all actions that the characters can take. You choose the path so you get it from beginning to end.
-If on the other hand follow what I propose the game itself would be more like a challenge and it would be easy to add a way out for those that dislike it, you just need an option like disable NTR and lock all stats that Eric has with the girls at 0. It would let you play the game without fear of NTR, albeit the experience would be more interesting if you tried and won.
Lastly about your financial point... it worked like that when the adult market started, but now... not so much. Overall this is something that happens a lot, first we go into games that try to offer a bit for everyone, but then when the number of games increase, people won't be able to support all of them, so they will only support those that give a concept that attracts them more, that has a biggest representation of their fetishes. Overall what truly matters is the concept and that people like it. Personally I'm the first one that dislikes pure unavoidable NTR from beginning to end, I can understand to use it at the beginning as a resource to motivate the story, but later on I only want it to exist in the avoidable version.
I totally agree with you, in fact the mother is kind of messed up to submit so fast. But well overall in the aspect of competition, I only ask for a competition that I can win, starting at an unfair point it makes it more sweet the victory.
About this part I suppose you didn't notice the quality drop in storyline, the incomplete parts because of a rushed kicking of Eric and how the game tried to generate a different antagonist by using Alice and forcing her character to evolve that way out of nowhere.
