Hard to say, since I believe this might be a small studio/production.
Think 1.6 is in preview atm.
I think that the game has a rather low acceptance, which I suppose doesn't help the Dev to frequently update the game.
In any case, seeing that half of the LIs aren't exactly interesting for most harem players, it's logical that the income is rather residual.
In my opinion the dev would be better off removing Scarlet, Evelyn and Bella from the game (or modifying their stories to remove the parts that make potential fans of the game leave), as they are now, they are basically LIs thrown into the trash. Regarding Gabriella... personally I wouldn't include a "LI" who is strictly lesbian and in love with another of the LIs in the game, but at least you can reject her without there being anything lesbian. But this is still throwing another character in the trash.
And, including an NTR route for one of the LIs that may actually be of interest wasn't a brilliant idea.