Why does the game have no coop?
Because multiplayer doesn't have to go into literally everything, and some experiences are best enjoyed alone. I'm in the process of making my own game that plays mostly like Dragon's Dogma, mixed with both DD's and some of Dark Souls' subsystems (specifically the older ones). There is a planned feature that will allow you to not just let your pawn equivalent be hired by other players, but will also let players have their computer-controlled pawn invade other players' worlds in a similar fashion to Gravelording, of which these different aspects are tied to specific factions.
Even in this case, I do not plan at any point to allow cooperative or competitive multiplayer to the game, as that is not the experience I'm aiming for. The sooner people like you get it in their heads that not every experience has to be made for you and your friends, the sooner you can enjoy such things to their fullest. Monster Hunter exists as well.
"B-But sales will be higher!"
Literally don't give a single shit. I'M making the game that I want to play, which is one of several key components of why games made today are shit; games in the modern age with moderate to high budgets are very rarely made because that is the game the developers want to play, instead it is the game that shareholders, C-suite, and middle management decide we get to play, in that order. Not that the overwhelming majority of developers are worth shit these days anyhow, but it still doesn't help.