hard tay, I've been buying digital games from last gen, never bought a physical disk for this gen. The companies never seem t ore lease digital sales numbers weather the games are succesful or not so you can't just say that it was a flp because they didn't release the numbers.
I'd say the best way to tell is if the game in question dies off. if it is discontinued, chances are it wasn't profitable, if it comes back revamped a year later, chances are they mades something from the previous game.
Another decoder that can be used is in online centric games like cod, the game lobbies tells you how many people are online. keeping track at early samples of those numbers and comparing them can give you an idea theoretically as well.













