glaurung, I'm not saying that this is a particularly grindy game, but consider:
First, you don't
know all this before you've played the game. In-game there are all sorts of things keeping you from progressing with the girls and with the quests, and (especially since girls' stats are hidden) it's not always obvious whether you're stuck because you need to grind affection/repeat events, level your stats, hit some particular event trigger (at a particular day/time/place), wait around for a timed event (like the Primrose prosecution), or focus on some other part of the game to unlock a clue or spell. So it's very easy to waste actions and grind fruitlessly/inefficiently. Take Primrose, for example: you can read books by yourself while working (grinding coin, and some affection?) or in the reading room with her (grinding affection). On a first playthrough it's not obvious which is the better strategy.
Second, OK, so altogether you need about 100 coin (isn't it sometimes 15 for agility training, BTW?). And on the first playthrough you earn, IIRC, 3-5 per morning in the library or Callie's store. That would be 20-30 mornings just to earn cash. Sure, you can earn more by going boar hunting once you have leveled up pathfinding, but that's gated behind meeting the dryad, leveling up your magic, and staying chaste for three days, twice. A player who goes straight for that will probably have no cash problems. One who focuses on other quests may find themselves having to work for many days to be able to afford to advance their magic training or level up agility.
Which I think goes back to my main point: it's not really the grind that is the challenge. It's more knowing the order in which you should do things, and not getting caught in situations where you can't use the time efficiently (e.g. where all useful action are only in the afternoon). Which on a first playthrough is a lot down to luck.
PS: I don't really agree that Evelyn is the most difficult, since her progression is fairly straight-forward and self-contained (like Primrose's). I'd argue that Callie's is by far the most non-intuitive, since it's gated behind first the Knock spell (library, time delay) and Skeleton Key (Nell/stables), then Morph Sexuality (Primrose secret, Leanan Sidhe)—parts of the game with no obvious connection to her.