Why bother? You're in the minority so the dev would have to dedicate sometimes weeks or months to add something only a small subsection of their paying customers would appreciate or even look at. Remember most gooners generally don't tend to play a game all the way through so adding in a "good ending" seems redundant when your average gooner will hit the CTRL the moment they hit new game.
It's mostly a story problem, when you create NTR games with no nuance and just create MC's with micro pensises, 1D personalities and their narrative arc is to just be emasculated and cucked you create no incentive for the player to get invested in your MC. You have to create MC's that the player wants to see a good ending for first.
You know that the dev dedicate times to allow this "good end" to happen, they even make a scene here even if it's not a sex scene in most of the game who had "true love"/"good end". Making one or two sex scene doesn't cost that much. If it was about cost, why are they allowing this "good end" path to happen? Why are they working on it? Some NTR game don't even bother, the option is here, so why putting a bit of time and effort into it?
Maybe it's a way of saying that the MC is so pathetic that he don't deserve to be with the woman or that even if he save the girl, it's not enough to deserve to have sex with her, i dunno.
it seems to be you save the girl and you get ALL scenes without face censors and overlays.
It's a bit more complicated. If you do the investigation AND get the 15 000, you get the good end and you can unlock on the pc all the scene but you will not have the context and the slow progression of the corruption.
However, if you didn't do the investigation, you have two other path, let's call path a and b. path a you didn't get the 15 000 (i dunno what happen). path b you get the 15 000 but the men who manipulate you explain that the 15 000 money was only the price of the vase you broke, you have to pay the interest of 120 000! So here is the grind to get this when the FMC get corrupt to get 120 000 too. At the end, the girl is fully corrupt so you lose her even if you get the 120 000. Here you have path b1 where you get the 120 000 and you unlock the scenes without censors and overlays as you say + a special scene where the MC fully understand the dept of how fucked she is now.
If you don't, the girl get the 120 000 for you, not because she still like you but as an excuse to still have sex. You didn't unlock the scenes uncensored but you can buy them online with the pc in your room.