I don't think this was ever supposed to be a skill based game or anything like that. This is a visual novel, but in an interesting and unusual format.
This is a game where you don't have the capacity to change, but the enemy does; i.e. now you have to deal with their changes as they come, while you lack that capacity.
Look at this as an inversion of the traditional grind-based game if you must, but it is still just a very creative visual novel.
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This is a fun theory, until you realis the fight sequences are the exact same on every playthrough, nothing changes, and the hero's progress is entirely scripted. I was so excited to play this game and it turned out to be a sad attempt at a conclusion you already know before you start with a method that undermines the entire point.
It is not a theory, this is literally a visual novel. The listed genre is "Interactive Fiction".
On top of that, there's a lot of grind based games that are exactly the same. You use the exact same moves and skills over and over again, nothing changes. You just deal that extra bit more damage for that extra hour of grind, and then try again.