I got 100 hours out of Stardew Valley. So by that logic it should have cost $60 too.
It could be. It could be $60 and no one would bat an eye. Except for the fact that no one knows the developer and they practically have to price it the way they do or else no one would buy it. Octopath Traveler is a AAA game and the well known devs are going to price it however they want b/c of that. A game being 2D doesn't mean it can't be full price. That's an incredibly naive sentiment to have. It's all about how the developers want to price it and what you're willing to pay for it.
You know that thing when you uhhh...and then you...hmmm. But then you have to...umm, Yuh.